England and Wales Court of Appeal (Civil Division) Decisions

IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM NOTTINGHAM
HIS HONOUR JUDGE INGLIS
4NG15127

		Royal Courts of Justice Strand, London, WC2A 2LL
		22/05/2009

Lady Justice Smith:

1. This appeal concerns the liability of employers in the knitting industry of Derbyshire and Nottinghamshire for their employees' hearing loss due to exposure to noise at a lower level than that which has in the past generally been recognised as giving rise to liability.

Historical Background

2. For well over a hundred years, it has been known that prolonged exposure to loud noise causes deafness. Such deafness was long regarded as an unavoidable occupational hazard. In the early 20^th century, ear protectors were developed and were supplied to some members of the armed forces during both world wars. But it was not until the second half of the century that any real interest was taken in preventing noise-induced deafness in industrial workers.
3. In April 1960, the government of the day instructed Sir Richard Wilson to chair a committee to report on the problems of noise. The committee's first report was published in 1963. In the same year, in reliance on that report, a Ministry of Labour publication entitled 'Noise and the Worker' drew the attention of employers to the need to protect their workers from excessive noise. At that time, scientific knowledge was not such that it could be said with confidence at what noise level harm was likely to occur. A rough guide was given that workers who were regularly exposed to noise of 85 decibels (dB) at any frequency for 8 hours a day should be protected.
4. Further research was carried out during the 1960s, in particular by a team led by Professor W. Burns, Professor of Physiology at the University of London and Dr D.W. Robinson, then head of the acoustics section of the National Physical Laboratory. In 1970, the result of their work was published as 'Hearing and Noise in Industry'. By that time, a method had been developed of measuring noise levels by reference to the weighted average for all frequencies (expressed as dB(A)) and for assessing the equivalent noise exposure over an 8 hour working day (expressed as dB(A)leq or more recently dB(A)lepd). Burns and Robinson explained that they were now in a position to predict the degree of risk of hearing loss to groups of an exposed population of varying susceptibility from various levels of noise exposure. Their work would make it possible to prepare a code of practice for employers. They discussed the possibility of establishing a limit of maximum exposure as follows:

"The limit can be set at a variety of levels according to the ultimate risk judged to be acceptable and we suggest that it should not be set higher than 90dB(A) for normal continuous daily exposure which is likely to persist for many years."

5. In 1968 and 1971 two further editions of 'Noise and the Worker' were published. The gist of the advice given in the third edition was that, if employees were exposed to noise in excess of 90dB(A), there should be a programme of noise reduction or hearing conservation. That level of noise exposure corresponded approximately to the 85dB which had been the level at which action was recommended in the first edition of 'Noise and the Worker'. The third edition encouraged employers to reduce noise exposure below the maximum permitted level in order to avoid risk to the hearing of 'the minority of people who are exceptionally susceptible to hearing damage'.
6. A Code of Practice, based on the work of Burns and Robinson was published by the Department of Employment in 1972. Its main messages were that employers must measure the noise in their premises and, if the noise level was 90dB(A)leq or above, must take steps to reduce the noise at source and, if that was not practicable, to provide ear protectors. The Code of Practice also explained that protection from noise of 90dB(A)leq would not protect all workers from hearing damage; some harm was likely to be caused to some susceptible workers by noise below that level.
7. A set of tables first published in 1973 by the National Physical Laboratory (the NPL tables) showed the relationship between noise dose and the expected extent of hearing loss of persons with different degrees of susceptibility. Noise dose was based upon the daily exposure adjusted for the number of days' exposure in the year and the number of years' exposure. These tables were based on the work of Burns and Robinson. They were republished in 1977 in a more user-friendly form but the underlying science was the same as before and indeed it remains valid today. The tables demonstrated the harmful effect of prolonged exposure to noise below 90dB(A)leq but, because they were based on empirical data and because the data available for these lower noise levels was limited, there was some dependence on extrapolation. The degree of predicted risk arising from exposure to these lower levels of noise is therefore less certain than that caused by noise over 90dB(A)leq. That is of significance in the context of this appeal which raises the issue of when employers ought to have taken steps to protect their employees from exposure to such lower levels of noise.
8. Until 1989, the Government of the United Kingdom made no attempt of general application to regulate noise exposure in industry. In 1974, regulations were made to control noise in the woodworking industry and in tractor cabs. The regulations required employers to reduce noise to the greatest extent practicable and to provide ear protectors where persons were likely to be exposed to noise at or above 90dB(A)leq.
9. In 1975, a sub-committee of the Industrial Health Advisory Committee, set up after publication of the Code of Practice in 1972, reported on the problems of framing protective legislation. The gist of this report was that the noise limit recommended by the 1972 Code had widespread acceptance although it did not eliminate all risk of harm. 90dB(A)leq was the most practicable standard although a lower limit should be considered at regular intervals.
10. In 1975 an international standard was published (ISO1999). This proposed a formula by which hearing loss could be predicted from various levels of noise exposure. It was not easy for a lay person to use. ISO1999 did not suggest limits of tolerable exposure. It said that that was the province of 'competent authorities' who would demand the institution of hearing conservation programmes if limits were exceeded. It mentioned that 'in many cases', 85 to 90dB(A) equivalent continuous sound level had been chosen.
11. In 1976, a British Standard was published (BS 5330:1976). This was based on the work of Burns and Robinson and explained the relationship between noise exposure and the expected incidence of hearing disability. The foreword stated that determination of a maximum tolerable noise exposure was outside the scope of the standard and referred the reader to the 1972 Code of Practice.
12. In 1981, the Health and Safety Executive (HSE) issued a consultative document 'Protection of Hearing at Work' which included draft regulations and a draft approved code of practice. The proposed level of protection was at or above 90dB(A)lepd. These draft regulations were not promulgated.
13. In 1982, a draft directive was published by the European Commission, proposing a general limit of 85dB(A)lepd with ear protection to be provided at or above that level with medical surveillance and routine audiometry for all employees exposed at or above that level. This was greeted with some dismay by industry and was withdrawn in 1984. A further draft directive was published and was promulgated in 1986. This required member states to enact legislation which would, inter alia, require employers to provide ear protectors and information as to risks where employees were exposed to noise likely to exceed 85dB(A)lepd. Medical surveillance was to be made available to all exposed employees by means of access to a doctor. Thus, the only change of significance between the 1982 draft and the 1986 directive was that responsibility for medical surveillance would not fall on the employer but (at any rate in this country) would be satisfied through the provisions of the National Health Service. The Noise at Work Regulations 1989 (SI 1989 No 1970) implementing the directive came into effect on 1 January 1990.
14. For the sake of completeness, although not relevant to this appeal, I mention that, in 2003, the European Commission issued a further directive imposing more stringent requirements. The Control of Noise at Work Regulations 2005 (SI 2005 No 1643) gave effect to that directive. Inter alia, they introduced a maximum permitted noise level of 87dB(A) and required employers to provide ear protectors to workers exposed to 85dB(A) and to make them available on request to workers exposed to 80dB(A).

The litigation below

15. This appeal arises out of a group of seven claims heard by His Honour Judge Inglis, sitting as a deputy high court judge in Nottingham in which judgment was handed down in February 2007. The seven claimants had been employed by four different employers in the knitting industry at factories in Nottinghamshire and Derbyshire. All had been exposed to noise in excess of 80db(A)lepd but less than 90dB(A)lepd. The seven claims were selected from about 700 outstanding claims of a similar nature. The claims were never the subject of a group litigation order but, for all practical purposes, were treated as group litigation.
16. The judge dismissed all seven claims. In six cases, he held that the claimant had failed to prove that he or she was suffering from noise-induced hearing loss. In the remaining case, he held that the claimant, Mrs Stephanie Baker, had suffered noise-induced hearing loss. From 1971 until 1991, she had been employed by a knitting company which, during her employment, was part of a group known as Nottingham Manufacturing Ltd, later part of the Viyella Vantona group and later still part of Coats Viyella PLC. At the time of judgment, the company was known as Taymil Ltd and is now known as Quantum Clothing Ltd. The ambient noise at her places of work was about 85 to 86dB(A)lepd. Her employer provided her with ear protectors in 1989 and she wore them thereafter. She had been exposed to noise at or above 85dB(A) lepd for about 18 years. The judge dismissed her claim because he held that the employer had not been in breach of duty during the material time either at common law or under section 29 of the Factories Act 1961. Mrs Baker appeals against that holding, with the permission of the trial judge, contending that her employer, the first respondent, had been under a duty to provide ear protectors from about 1972 or alternatively from some later date but before 1989.
17. Although the judge found against all the other claimants, he made holdings about the theoretical liability of the other three employers involved in the group litigation. Those holdings were intended to govern any other case against those employers brought by other claimants in the larger group who were able to demonstrate noise-induced hearing loss.
18. First, he held that there was no liability at any material time to protect employees from noise exposure below 85dB(A)lepd. All parties are content with that holding.
19. Second, he held that two employers, Meridian Ltd (part of the Courtaulds Group) and Pretty Polly Ltd were liable for exposure to noise of 85dB(A)lepd or above from early 1985. Those two employers were dissatisfied with those holdings and obtained permission to cross-appeal in these proceedings, notwithstanding that the issues are at present hypothetical. Meridian Ltd, the second respondent, contends that it should not be held liable until 1990 and Pretty Polly, the third respondent, contends for a date of liability of 1986, the date at which it in fact provided ear protectors for workers exposed to noise at and above 85dB(A)lepd.
20. Finally, in respect of a further defendant employer, Guy Warwick Ltd, which is not before the court as an appellant, he made a holding which I find unclear, to which I will refer again below.

The judgment below

21. I must begin this section by paying tribute to Judge Inglis's judgment. Although, as will be seen, I will be critical of some its conclusions, it is well structured and lucidly expressed. It is necessarily quite long; the hearing lasted 18 days and the judge had to consider a huge number of documents. But the evidence, argument, reasoning and conclusions are (save for one conclusion) set out clearly and logically.

Does noise below 90dB(A)lepd damage the hearing?

22. The judge's first task was to decide, on the basis of the published work and expert evidence before him, whether exposure to noise below 90dB(A)lepd is harmful to the human ear and, if so, since when that has been recognised. At paragraph 26 of the judgment, he concluded that the work of Burns and Robinson in the late 1960s and early 1970s, confirmed by later work, showed that noise exposure between 80 and 90dB(A)lepd does give rise to some risk of harm. Below 85dB(A)lepd the risk is so low as to be properly described as minimal. On that basis, he said that there had been no duty to protect employees from it at any time material to the actions. However, he continued:

"Above 85dB(A) the risk accelerates up to 90dB(A). In the high 80s, given long enough exposure, significant hearing loss may be expected in at least a substantial minority of individuals."

23. That important finding is not challenged in this appeal and it is not therefore necessary to examine its evidential basis. There was before us some argument as to the precise extent of the risk between 85 and 89dB(A)lepd. Mr John Hendy QC for the appellant contended that the NPL tables show that, after 40 years' exposure to noise in that bracket, about 7% of the exposed population will suffer 50 decibels of hearing loss in the speech frequencies - a very significant hearing disability. For the second respondent, Mr Christopher Purchas QC, looking at other published materials, contended that this was a serious over-estimate. He submitted that the NPL tables are unreliable at the lower levels of exposure. In my view, the judge was right not to attempt to resolve this dispute and to make the general statement I have quoted above. It sufficed for his judgment and it will suffice very well for the purposes of this appeal.
24. It is important to note that the judge's conclusion above was based on scientific work first published in 1970 and fully explained by 1973. That is not to say that, in 1973, a lay person would have understood the extent to which noise in the 85 to 89dB(A)lepd range was likely to cause harm. However, it does mean that a suitably qualified expert would have that understanding by 1973.

What should employers have known about the risk of exposure to noise below 90dB(A)lepd?

25. The judge then noted that scientific knowledge of the risk was relevant to the duty of employers but it was necessary to consider what employers knew or ought to have known at various times and what they should have done with their actual or imputed knowledge. So the judge considered the gradual progress made towards statutory regulation of noise and the various official published documents which provided guidance for industry. He referred to the documents I have already summarised.
26. The judge also considered a great number of other documents of less general significance and the expert evidence called before him as to the attitude of industry to the problems of noise over the years. Mr T.P.C. Bramer, BSc(Eng) CEng MIET FIOA, who has worked as a noise consultant for some 37 years, gave expert evidence for Meridian/Courtaulds. His evidence was that, in the 1970s and into the mid-1980s, he used to advise employers that they must protect workers exposed to 90dB(A)lepd and above. That, he said, was the standard approach and was taught at training courses; it remained so until the mid-1980s. He said that his advice changed in the mid-1980s when it appeared that European legislation would require a first action level at 85dB(A)lepd. He agreed in cross-examination that the advice he gave was in answer to the request of employers as to how they should comply with the relevant legislation rather than how they should avoid reasonably foreseeable risk of harm.
27. Mr Currie, a consultant engineer who gave expert evidence for Courtaulds and Mr K.A.Worthington who gave expert evidence for Pretty Polly agreed that the HSE and Factory Inspectorate concentrated their advice and enforcement on the 90dB(A)lepd level.
28. There was no expert evidence from the claimants to contradict these views.
29. The judge considered that the evidence showed that, even by the early 1980s, there were still many workers exposed to more than 90dB(A)lepd and that the official approach to enforcement was to concentrate on that problem, leaving lower noise levels aside.
30. That completed the judge's survey of the information available to all employers. He did not express any view about what that information should have been imparted to employers about the risks associated with noise in the range between 85-89dB(A)lepd. Instead, he embarked upon consideration of the state of actual knowledge of the four defendants. That entailed some examination of the published documents which the defendants admitted having had in their possession and the internal documents which remained available and had been disclosed in the proceedings.

Courtaulds

31. In the case of Courtaulds, the internal documentation started from 1982 because it came from the personal archive of Dr Peter Cooper who gave evidence for Courtaulds at the trial. Dr Cooper's interest and involvement with industrial noise began in late 1982 but he accepted that Courtaulds must have had some relevant documents from an earlier time. The disclosed bundle included a memorandum issued by the legal and medical departments during the first half of 1983. This 'strongly recommended' that, because of the risk of hearing loss, 'ear protectors should be provided for all those who may be exposed to noise within the range 85-90dB(A)leq'. This coincided in time with representations made by Courtaulds, in February 1983, in opposition to the proposal in the EEC draft directive that protection should be provided at 85dB(A)lepd. These representations were made on economic and competition grounds. It was said that the provision would be 'increasingly burdensome and very difficult to enforce'. It was estimated that provision for the 12,000 employees in this category would cost 'several hundred thousand pounds a year'.
32. The documentary evidence was supplemented and explained by oral evidence, mainly from Dr Cooper who, from late 1982, had been put in charge of noise control in the Consumer Products Group, the division of Courtaulds which included clothing manufacture. There was no evidence of anything which had occurred before then. He described the steps he had taken, through a Noise Committee, to investigate the noise position in this division. The minutes of his committee show that it took a year to identify areas of over 90dB(A)lepd and areas of 85 to 90 dB(A)lepd. The attitude of the committee was to take immediate action (ie to require compulsory use of ear protectors) for areas over 90dB(A)lepd but, in respect of 85 to 90dB(A)lepd, action would be 'medium term with the aim of securing 75% acceptance of hearing protection by mid-1985'. It is not clear from Dr Cooper's evidence exactly when Courtaulds provided ear protectors for workers exposed to 85 but below 90 dB(A)lepd.
33. At paragraph 56, the judge expressed his conclusion in respect of Courtaulds as follows:

"No large company who responded to the consultation document (HSC 1981) or read the background document and was aware of the EEC proposals in 1982, and one that then took part in the debates trying to fend off compulsory protection at 85dB(A) on economic grounds, but not on grounds that such levels of exposure were not harmful, could be said to be ignorant of the facts by the beginning of 1983 at the latest."

34. The above reference to 'no large company' suggests that the judge's conclusion in respect of Courtaulds was affected not merely by the content of the documents and the evidence called but also by the company's size and resources. He had noted that Courtaulds was a large company; until the early 1980s, it had had 100,000 employees in six divisions. By the end of the 1980s, the overall numbers were down to 48,000 with about 20,000 in textiles.

Taymil/Quantum

35. The judge then turned to Taymil Ltd (now Quantum Clothing Ltd). He noted that Mrs Baker's employer, Simpson, Wright & Lowe Ltd, became a subsidiary of Nottingham Manufacturing Company PLC in the early 1970s. During the 1970s and early 1980s, that company had over 12,000 employees. However, the judge accepted evidence that each company within the group had been run with a large degree of independence; there had been no central health and safety function. Nottingham Manufacturing had merged with Vantona Viyella PLC in 1985 and the resulting entity became a subsidiary of Coats Viyella PLC in 1986. That was a large group with about 68,000 employees working in various divisions.
36. Only a few documents had been disclosed. The oral evidence suggested that Nottingham Manufacturing had had the 1972 Code of Practice and there was evidence that, in June 1983, the Midland Insurance company had measured the noise levels at the factory where Mrs Baker worked. The survey report referred to the 90dB(A) limit but said that hearing protection should be worn in all areas where the level was above 87dBA. There were a number of areas with such noise levels. A guide to preparing a noise policy was appended in which it was said that a noise reduction programme should aim at reducing noise to 84dB(A) or less if practicable. There was also a noise survey of another factory in the group dated August 1984 in which the writer referred to a company policy of taking 85dB(A) as the exposure threshold level. However, the judge found that there never was such a policy. Witnesses whose evidence he accepted said that the limit 'to be worked to' was 90dB(A).
37. The judge found that no steps were taken in respect of exposure between 85 and 89dB(A)lepd. I interpose to say that he must have meant that no steps were taken until 1989 when Mrs Baker and, presumably, employees working in similar conditions were given ear protectors. However, he noted that Mr Douglas Watson, the group insurance and risk manager from 1974 to 1988, had admitted that he was aware of the EEC draft directive in 1982 and of the debate which followed, which he had discussed with insurers. At paragraph 61, the judge referred again to the documents I have just reviewed, finally mentioning again the 1983 document from Midland Insurance and continued:

"…but it does not provide the information that means that management at Nottingham Manufacturing were in a position of knowledge and understanding that set them apart from what I take to be the understanding of the great majority of employers, that 90dB(A)lepd was the official limit that had to be worked to. I do not think it is shown that Nottingham Manufacturing had a greater than average degree of knowledge."

It is to be noted that, for the second time, the judge did not say when he thought that a company with an average degree of knowledge ought to have known and acted upon the knowledge that there was a risk of hearing damage from exposure between 85 and 89dB(A)lepd.

Pretty Polly

38. In considering the position of Pretty Polly, the judge observed first that the company had always been a subsidiary of a larger group of companies. In its heyday in the early 1980s, the company had about 1,500 production employees. From 1982 until 1994 it had been part of the BTR group which had over 42,000 employees. The judge treated Pretty Polly as 'a large company' although it was much smaller than Courtaulds.
39. The judge noted which public documents the company had had in its possession and reviewed the internal documents. There was nothing to suggest that Pretty Polly had received a direct recommendation from its legal or medical departments (such as Courtaulds had received) and nothing to suggest that it had taken part in the debate on the 1982 draft directive. There was evidence that, in 1975, a Factory Inspector had found noise levels of 89dB(A) but had not recommended that any steps be taken. Also, there was evidence that the company's insurers had advised (at an uncertain date probably in the late 1970s or early 1980s) that there was some risk of harm to employees exposed to noise levels below 90dB(A) and had recommended that levels should be reduced where possible; 90dB(A) was to be regarded as a ceiling rather than a safe level. Also, there was a memorandum written by Mr John Butler from the works study department in about December 1982, which advised that 90dB(A) must be regarded as a maximum and that noise at that level involved accepting a certain risk of hearing damage. It continued:

"If we as a company feel that we require a zero risk of hearing damage for our employees, then no person should be exposed to a noise level of more than 80dB(A) for an 8 hour day."

There followed a table (apparently taken from ISO:99 of 1975) which showed the percentage risks of hearing damage of undefined severity which could be expected to arise from so many years of exposure to 80 and 85 dB(A)leq.

40. The judge's conclusion in respect of Pretty Polly was expressed at paragraph 66 thus:

"There is no evidence that anyone at Pretty Polly turned their mind towards any evaluation of the risks below 90dB(A) before 1982. It is not really likely that they did so. It is plain from Mr Butler's documents that by that year he had done so. Indeed, it is unlikely that a company of that size where there had been some collection of materials and where they cannot have been unaware of the EEC proposals and the very public debate that followed, could not have known that there was a real case to be made that exposure below 90dB(A) could cause levels of hearing damage that should be guarded against. I would put actual awareness of the nature of the real risk below 90dB(A), as with Courtaulds, as having arisen by the beginning of 1983."

Guy Warwick Ltd

41. Finally, the judge considered the position of Guy Warwick Ltd, which had employed one of the claimants. The judge described it as a small company. It had four factories with a total of about 400 employees. It was formed in 1977 and went into liquidation in 1992. There was no evidence that anyone at this company knew about the Code of Practice or indeed anything about noise. No surveys were ever done. The judge observed that the question of whether this company was in breach of duty to its employees would have to be judged 'on the basis that they had no actual knowledge of the relevance of noise to their operation'. Once again, there was no finding of when a company with no actual or special knowledge should have known of the risks of noise exposure below 90dB(A)lepd.

Submissions

42. Having completed his generic findings of fact, the judge turned to summarise the submissions of the parties. The claimants were contending that, at common law, the employers had been under a duty, from 1963, to warn their employees of the risks of exposure to noise and to provide them with ear protectors. That duty extended to all noise in excess of 80dB(A). It was accepted that it was not practicable to reduce the noise emitted by the kind of machines involved in this case. The claimants submitted that, once the risk was known, it was obvious that ear protectors could and should have been provided but were not. The provision of appropriate protection and instruction was not expensive or difficult. The judge immediately indicated his acceptance of that last submission. At the end of paragraph 73, he said:

" The evidence does not show that at any time the cost of implementing a policy of voluntary hearing protection at levels below 90dB(A) was such that a reasonable employer could use cost or difficulty as a valid reason for not having such a policy."

43. The judge recorded that the heart of the claimants' submission was that a recommendation of the kind promulgated in the 1972 Code of Practice (that the main risk arose from exposure at and above 90dB(A)lepd) had no place in the assessment of whether an employer had been in breach of his duty either at common law or under the Factories Act. The question for the employer was not: 'what do I have to do to comply with the legislation and guidance?' but 'what do I have to do to avoid foreseeable risk of injury to my employees?'
44. For the defendants, it was argued that the 1972 Code of Practice provided authoritative guidance as to the level of exposure at and above which there would be a breach of the employer's duty of care. That was 90dB(A)lepd and it was reasonable for employers to have been guided by that during the 1970s and 1980s.

The judge's decision on common law liability

45. The judge cited extensively from a number of authorities including the classic statement of the employer's duty of care in a developing field of knowledge as expounded by Swanwick J in Stokes v Guest, Keen and Nettlefold (Bolts and Nuts) Limited [1968] 1 WLR 1776 at 1783:

"From these authorities I deduce the principles that the overall test is still the conduct of the reasonable and prudent employer, taking positive thought for the safety of his workers in the light of what he knows or ought to know; where there is a recognised and general practice which has been followed for a substantial period in similar circumstances without mishap, he is entitled to follow it, unless in the light of common sense or newer knowledge it is clearly bad; but where there is developing knowledge, he must keep reasonably abreast of it and not be too slow to apply it; and where he has in fact greater than average knowledge of the risks, he may be thereby obliged to take more than the average or standard precautions. He must weigh up the risk in terms of the likelihood of injury occurring and the potential consequences if it does; and he must balance against this the probable effectiveness of the precautions that can be taken to meet it and the expense and inconvenience they involve. If he is found to have fallen below the standard to be properly expected of a reasonable and prudent employer in these respects, he is negligent."

46. Then at paragraph 87, he reached the kernel of his judgment on the questions of duty and breach at common law. He said:

"87. There is no doubt that research into the question of what risks to the hearing of employees exposure below 90dB(A)leq posed would have yielded the answer that 90dB(A) was not a natural cut off point, and that there were risks to susceptible individuals below that level. Indeed, the 1972 Guidelines themselves made that clear. From the early 1970s, certainly by 1976, with the publication of BS5330 and of ISO99 in the previous year, the information was available if researched to give an indication of the level of the risk. It was a level of risk that came, by the end of the 1980s, to be seen as unacceptable if not accompanied by at least voluntary protection, though the 90dB(A) limit had remained, both in 1975 and in 1981, the proposed regulatory standard in England. In the end though, I am not persuaded that employers in industry who conformed to the maximum acceptable level of exposure in the 1972 Guidelines were in breach of their duty of care to the employees who were exposed over 80 dB(A)lepd. In rejecting the primary case for the claimants, I acknowledge that I do not see the issue as only one of foreseeability. It would, in my judgment, be futile to hide behind the 1972 Guidelines for that purpose, or behind the third edition of 'Noise and the Worker', when the documents themselves proclaim that the level proposed will not be safe for all workers. But good practice as informed by official guidance has in my view to be taken into account as well. The guidance as to maximum acceptable levels was official and clear. It would in my view be setting too high a standard to say that it was incumbent on employers to ignore it and to reach and act, even as early as the 1960s, on a view that the standard set was inadequate to discharge their duty to their employees. To put it in the context of Swanwick J's judgment, complying with 90dB(A)lepd as the highest acceptable level was, I think, meeting the standards of the reasonable and prudent employer during the 1970s and 1980s certainly until the time when the terms of the 1986 directive became generally known in the consultative document of 1987. I accept that this means that employers were not bound in the discharge of their duty to ask the question "Who are those at risk in my factory and how big is the risk?" It is a question that none of them in this case asked. But the effect of the maximum acceptable level in the Guidelines means, in my judgment, that they were not in breach of their duty for not asking it."

47. In paragraph 88, the judge said that he considered that there was room for the 'greater than average knowledge' that would inform the steps that individual employers should have taken at an earlier time than the late 1980s. Reflecting his previous findings of fact, he held that both Courtaulds and Pretty Polly (but not Nottingham Manufacturing/Taymil/Quantum) had had such greater than average knowledge by the beginning of 1983. He then observed that putting a conservation programme into action, accompanied by information and instruction 'is not to be done in an instant'. He held that those two employers were in breach of their duty at common law in respect of exposure at 85 dB(A)lepd and above from the beginning of 1985. In other words, he allowed them 2 years in which to provide hearing protection accompanied by information and instruction.
48. It must be noted at this stage that the judge did not give any reasons for allowing two years after the date of knowledge. Also, it is not entirely clear what the judge intended to include in the two years. It may be that the two years was intended to cover the time taken to measure the relevant noise levels as well as making provision for protection. That is not without importance. Measurement does take some time and the evidence suggested that it took Courtaulds a year to measure all the noisy areas in the relevant division. But the judge does not seem to have considered whether companies with some departments or areas with noise levels over 90dB(A)lepd and some below ought to have discovered well before the 1980s which areas were which. If they had discovered that, time from the date of knowledge of the need to provide protection would need to cover only the provision of protectors and information.
49. More important even than that is the uncertainty about the effect of the judge's holding in paragraph 87. When I read the judgment, I thought that the holding in paragraph 87 meant that, for average employers, the date of knowledge was 1987 by reference to the publication of the consultative document on the 1986 directive. Later, from his holding that there was no liability in respect of Mrs Baker (who was provided with ear protectors in 1989) I inferred that he must have given her employers (who he said had no special knowledge) two years in which to react. However, Mr Robert Owen QC, who appeared for Quantum, submitted that the judge had held that there was no liability throughout the whole of the 1980s and that liability had only bitten when the Noise at Work Regulations 1989 came into force on 1 January 1990. It is unfortunate that this important aspect of the judgment should be left unclear. However, I can detect no sign of the judge making a holding by reference to the 1989 Regulations and I conclude that he intended to hold that, for average employers, which included Quantum Ltd and Guy Warwick Ltd, the date of knowledge was 1987 and the date for action - and liability in the absence of action - was 1989. I shall deal with the appeal on that basis but, before dealing with the appeal against the decision on common law liability, it is convenient to set out the judge's decision on breach of statutory duty.

The judge's decision on liability under section 29

50. At paragraph 90, the judge turned to consider liability under section 29 of the Factories Act 1961 which remained in force throughout the period with which this appeal is concerned. It provides:

"There shall, so far as is reasonably practicable, be provided and maintained a safe means of access to every place at which any person has at any time to work, and every such place shall, so far as reasonably practicable, be made and kept safe for any person working there."

51. The judge accepted the claimant's contention that a place of work might be unsafe by reason of the permanent or regular activities being carried on there. He accepted that, if the place of work is shown to have been unsafe, the burden of proof passes to the employer to show that it had done all that was reasonably practicable to make and keep it safe. Further, keeping a place of work safe might involve the provision of safety equipment such as ear protection. None of those holdings is challenged in this appeal. Indeed, they appear to me to be well-established law.
52. The contentious issue arose from the claimants' submission that the safety of a place of work was to be judged entirely objectively and not by reference to what was reasonably foreseeable at the time. After consideration of authority, the judge rejected the claimants' submission and held that the claimants' places of work had not been unsafe by reason of the noise to which they were exposed. That was because, he said, following an unreported decision of Rose J in Taylor v Fazakerley, the standard of safety in section 29 is governed by the general standard which ought reasonably to have been adopted by employers at the relevant time. At the end of paragraph 97 he put it in this way:

"…the question of whether a place of work is safe is really a jury question, to be answered in the light of all the circumstances prevailing at the time including what might reasonably have been foreseen by an employer."

The judge held that, in this case, the standard of safety would be exposure to 90dB(A)lepd. Thus the places of work were not unsafe and there was no liability under the statute. In effect, the judge held that section 29 did not add materially to the common law duty.

The Judge's final conclusions

53. The judge then dealt with a number of other general issues which are not material to this appeal. Finally, he considered the individual cases and, as I have already explained, held that only Mrs Baker had demonstrated any noise- induced hearing loss. Even in her case, the noise-induced element was only a small part of her overall loss and noise had made only a small contribution to her tinnitus. The judge said that, if damages were to be awarded for all her noise induced loss and tinnitus, he would award £5,000. That was on the basis that he had been wrong to dismiss her case on liability. It is common ground before us that that assessment was made on the assumption that Mrs Baker had been exposed in breach of duty for the whole period from 1971 until 1989 when she was given ear protectors. It was also common ground that, if this court were to hold that Mrs Baker's employers had been in breach of duty for part of the time between 1971 and 1989, her damages should be apportioned on a time basis.

The Appeal to this Court – Mrs Baker's appeal against Quantum Clothing Ltd

Section 29 of the Factories Act 1961

54. Mr Hendy's first submission was that the judge's approach to section 29 had been wrong. He had equated the duty under the statute with the duty at common law, whereas the statute imposed a higher duty on the employer. Mrs Baker should have succeeded under the statute. In addition, he submitted that she should also have succeeded at common law.
55. Mr Hendy submitted that the statute required that the judge should first consider whether the place of work had been safe. His primary submission was that this was a purely objective matter to which foresight of risk was irrelevant. If necessary, safety could be judged with the benefit of hindsight. A place of work could not be safe at one time and unsafe at another. If, with the benefit of hindsight, it could now be seen that the place of work was unsafe, it must have been unsafe at all times at which the same conditions had prevailed. If a person suffered hearing loss as a result of working without protection in a particular workshop, it could be said, without further consideration, that the place of work had been unsafe. The liability of the employer would turn on whether it could show that it had done all that was reasonably practicable to make and keep it safe. Mr Hendy accepted that considerations of knowledge and foresight would be relevant to what was reasonably practicable. It would not be reasonably practicable for an employer to take precautions against a danger of which he was not and could not be expected to be aware. Thus, whether at the first or second stage, what the employer ought to have foreseen would affect and might well govern liability.
56. As his secondary submission, Mr Hendy submitted that, if safety does depend upon knowledge or foresight of risk, it is the risk of any harm which should be considered. Here the risk of harm from noise below 90dB(A)lepd was known at the material times. The judge had accepted that the risk was recognised from 1972. Once that had been recognised, the judge should have held that the place of work was not safe, just as Popplewell J had held Mr Kellett's place of work was not safe in Kellett v British Rail Engineering Ltd (unreported transcript dated 3 May 1984) where the noise exposure exceeded 90dB(A)lepd. The reasoning of Popplewell J applied to a place of work where the noise level was 85dB(A)lepd just as it did at 90dB(A)lepd and over.
57. Third, he submitted that what the statute could not have had in mind, as a criterion for judging whether a place of work was safe, was whether an employer could reasonably have thought the degree of risk of harm was acceptable. That was the criterion which the judge had applied, in reliance on Fazakerley. That was a factor which could only be taken into account at the second stage, when considering reasonable practicability.
58. Mr Owen's submission on this point was that the judge's approach had been correct. Whether or not a place of work was safe depended upon what a reasonable employer ought to have considered acceptable at the time.

Discussion

59. I will begin by examining Taylor v Fazakerley (unreported 29 May 1989) on which Judge Inglis relied. In that case, the claimant had noise-induced hearing loss but liability was disputed. At the start of his judgment Rose J, as he then was, observed that it was 'common ground that exposure to noise levels in excess of 90 decibels is capable of damaging hearing, depending on the length of exposure'. The main issues in the case were what the noise levels actually were and for how long the claimant had been exposed to them. When he reached the question of breach of duty, without any reference to authority and without there apparently having been any discussion of the correct approach to the construction of section 29, Rose J said that, although section 29 was relied on, the essential question in relation to the statute and common law negligence was the same. He continued:

"The question is did the defendants, by reference to the standards which ought reasonably to have been adopted by them at the relevant time, expose the plaintiff to noise which they ought reasonably to have anticipated would or might, by reason of its level and duration, damage his hearing. "

It is apparent that he was there formulating the common law test. There is no reference to the safety of the place of work or the issue of reasonable practicability. That Rose J should formulate the test in that way is not surprising as it appears that the plaintiff was not contending that the statute imposed a higher duty than common law or even required a different evidential approach. So the judge was merely setting out the test that he proposed to apply in the instant case. He was not specifically considering the test under the statute, simply assuming, without argument, that it was the same as at common law.

60. Even by 1989, there was some jurisprudence on the correct approach to section 29 although the position was far from clear and the view was often taken that the duty under the section added nothing to the common law. However, since 1989, the law on this topic has developed, as I will discuss. Thus, although any dictum of Rose J usually commands the highest respect, this particular statement cannot be taken as a correct statement of the law on section 29 at least without discussion of the authorities and determination of which of the conflicting authorities are binding on the court. In my judgment, Judge Inglis was wrong simply to follow Rose J as he did.
61. I turn to the authorities which must be considered. Mr Hendy relies principally on Larner v British Steel [1993] ICR 551. In that case, the claimant was injured when part of a structure on which he was working fell on him. Careful examination of the structure would have revealed that it was cracked and unsafe. The claimant alleged a breach of section 29. The judge held that the examination in fact carried out by the employer (which had failed to detect the crack) had been sufficient and dismissed the claim. The Court of Appeal (Hirst LJ and Peter Gibson J) allowed the appeal, holding that the obligation to ensure that the place of work was safe was absolute, subject to the defence of reasonable practicability which had to be pleaded and supported by evidence. There was no requirement on the claimant to establish that any accident was reasonably foreseeable. As the judge had implicitly held that the place of work was unsafe and as reasonable practicability had not even been pleaded, the claimant succeeded on appeal.
62. The issue of what was the right approach to the question of the safety of the place of work had not been raised at the hearing below; the main issue had been the sufficiency of the inspection of the structure. As I have said, it was implicit that the judge had held the place of work to be unsafe. However, on the appeal, counsel for the employer sought to argue that, in order to satisfy the first stage of the section 29 enquiry (was the place of work safe?) the claimant had to prove that the danger was reasonably foreseeable by the defendants. As no objection was taken to the late introduction of the point, the Court allowed it to be taken and embarked on consideration of authority.
63. In favour of the need to show reasonable foreseeability, the Court considered obiter dicta in Taylor v Coalite Oils & Chemicals Ltd [1967] 3 KIR 315 and Morrow v Enterprise Sheet Metal Works (Aberdeen) Ltd [1986] SLT 697. In Taylor v Coalite, at page 319 Diplock LJ, as he then was, said:

"The occupier's duty in respect of working places is not to prevent accidents occurring to persons working at them but to take all such measures as are reasonably practicable to make and keep the working place safe for such persons. 'Safe' is the converse of 'dangerous'. A working place is safe if there is nothing there which might be a reasonably foreseeable cause of injury to anyone working there, acting in a way in which a human being may reasonably be expected to act, in circumstances which may reasonably be expected to occur."

64. That passage was plainly derived from Lord Reid's speech in John Summers v Frost [1955] AC 740, a case under section 14(1) of the Factories Act. That section provides:

"Every dangerous part of any machine …shall be securely fenced unless it is in such a position of such construction as to be as safe to every person employed or working on the premises as it would be if securely fenced…"

In Summers, it was held that the duty to fence arose only if it could reasonably have been foreseen that a person might be injured by the part in question. The argument accepted by the court in Taylor and Morrow and advanced by the employer in Larner was that 'safe' is the antonym of 'dangerous' and the same test must be applied to considerations of safety under section 29 as have to be applied to considerations of danger under section 14. So, the claimant must show that it could reasonably have been foreseen that the place of work was unsafe.

65. In support of the opposing view, the Court in Larner considered Robertson v RB Cowe & Co [1970] SLT 122. There the Inner House of the Court of Session had held that the test of safety under section 29 was an absolute one and reasonable foreseeability did not enter into consideration.
66. Hirst LJ also cited a passage from Munkman, Employers Liability 11^th Edn, 1990, where at page 292, the author expressed the view that 'safe' was a simple English word and there was no reason why the safety of a place of work should not be decided as a pure question of fact. He regretted the introduction of the 'vague and uncertain notion of foreseeability'. Hirst LJ thought there was force in that argument and noted that, if the concept of foreseeability were introduced, the distinction between the common law duty of care and the statutory duty would be virtually obliterated. Stating that the Court was free of binding authority, he held that the reasoning in Robertson was to be preferred and that the test of safety in section 29(1) is a strict one.
67. Peter Gibson J, as he then was, agreed with Hirst LJ on the main issue arising from the employer's failure to plead and prove reasonable practicability and, after undertaking an even more extensive review of authority, also agreed that foreseeability did not enter into consideration of the safety of the place of work. His reasoning was first that, on the plain meaning of the words, 'safe' meant 'safe' and not 'reasonably foreseeably safe'. To introduce that concept would be to reduce the protection afforded by the section for the protection of the worker. That was impermissible. It was not unfair on employers to impose this strict duty because the duty was qualified by the defence of reasonable practicability. To introduce the concept of reasonable foreseeability into the question of safety was effectively to equate the duty under the section with the duty at common law.
68. Second, Peter Gibson J cited the passage from Diplock LJ's judgment in Taylor, which I have quoted above. He pointed out that this passage required reconsideration in the light of the House of Lords decision in Nimmo v Alexander Cowan & Sons Ltd [1968] AC 107 and cited from the speech of Lord Guest at page 122:

"To treat the onus as being on the pursuer seems to equiparate the duty under the statute to the duty under common law, namely, to take such steps as are reasonably practicable to keep the working place safe. I cannot think that the section was intended to place such a limited obligation on employers."

69. Peter Gibson J recognised that there were Scottish authorities in support of both propositions under consideration. Like Hirst LJ, he considered himself to be free of binding authority and, for the reasons he had already given, he preferred the view expressed in Munkman. He held that, for the purposes of section 29, the safety of the place of work is to be considered objectively without regard to any concept of reasonable forseeability.
70. It is worth noting that, two years after Larner, in Mains v Uniroyal Englebert Tyres Ltd [1995] IRLR 544, the Inner House of the Court of Session reached the same conclusion on principle and after a comprehensive review of authority, during which they expressed their agreement with Larner. At paragraph 18, Lord Sutherland said:

"The initial part of the section is, in my view, clear. The duty is to make the working place safe. That means that there is a duty to prevent any risk of injury arising from the state or condition of the working place. There is nothing whatever in the section to suggest that the obligation is only to prevent any risk arising if that risk is of a reasonably foreseeable nature. Had that been the intention of Parliament it would have been perfectly simple for Parliament to have said so. If the duty had only been to take reasonably practicable precautions against reasonably foreseeable risks it is difficult to see how this section would have added anything to the common law. Where the statute is designed to protect the safety of workmen it is in my view not appropriate to read into the statute qualifications which derogate from that purpose. It cannot be said that this reading of section 29 imposes an intolerable or impossible burden upon employers. They have the opportunity of establishing that there were no practicable precautions which could have been taken to prevent their breach of the obligation."

In the immediately preceding passage, Lord Sutherland had made it plain that reasonable foreseeability of harm was relevant to the second question under the section, namely whether the employer had done all that was reasonably practicable to keep the place safe.

71. I have set out the reasoning in Larner at some length because it appears to me that the decision is binding on this court unless it has been overruled by higher authority or unless it can be shown to have been wrong or decided per incuriam. It is not suggested by Mr Owen that there is more recent authority on the subject in the House of Lords. However, Mr Owen submitted that the true effect of Nimmo was not as had been understood in Larner.
72. In Nimmo, the claimant had been injured when he fell from an insecure bale on which he had to stand while working. He relied on section 29, saying that his place of work was unsafe. He did not allege that it was reasonably practicable for the employer to have made and kept it safe. As is now well known, the principle to be derived from this case is that it is for the claimant (or prosecutor in a criminal case) to prove that the place of work was unsafe and for the employer to plead and prove that he had done what was reasonably practicable to make and keep it safe. The whole debate in that case was about the construction of the section and whether the phrase 'so far as reasonably practicable' was an integral part of the duty, breach of which had to be alleged and proved by the claimant, or whether, the claimant having proved that the place of work was unsafe, the expression 'so far as reasonably practicable' created a defence which the employer could raise and prove if he were able to. Their Lordships were in disagreement. Lords Reid and Wilberforce were of the view that the claimant had to prove not only that the place of work was unsafe but also that it would have been reasonable practicable to make and keep it safe. The majority, Lords Guest, Upjohn and Pearson held to the contrary; the claimant had only to prove that the place of work was unsafe and the burden of pleading and proving the defence of reasonable practicability lay on the employer.
73. The passage in Nimmo which Mr Owen seeks to rely on before us is to be found in the speech of Lord Upjohn at page 126 where he said:

"I think that the section requires the occupier to make it 100 per cent safe (judged of course by a reasonable standard of care) if that is reasonably practicable and, if it is not, to make it as safe as is reasonably practicable to a lower percentage."

Mr Owen's submission is that the words in parenthesis demonstrate that Lord Upjohn was saying that safety was not an objective consideration but was to be judged by reference to 'a reasonable standard of care'.

74. I confess that I am not sure exactly what Lord Upjohn meant by the expression in parenthesis. He may indeed have meant what Mr Owen says he meant. However, one thing is clear. That statement was not an essential part of the reasoning of Lord Upjohn's speech and was not in any way part of the ratio of the majority decision of the House. One cannot derive any assistance as to the approach to 'safety' from a passing reference such as that.
75. Mr Hendy sought to derive some support for his submission from part of the speech of Lord Goff of Chieveley in Austin Rover Group Ltd v Her Majesty's Inspector of Factories [1990] 1 AC 619 at pages 624G to 625C. At first sight those passages appear to support his submissions on 'safety'. However, the statutory provision under consideration in that case was section 4(2) of the Health and Safety at Work Act 1974, the wording of which is different in important respects from section 29. Thus I do not consider it right to draw any analogy. In any event, it appears to me that the other members of the House took a different view of the construction of section 4(2) from that of Lord Goff. For those two reasons, I do not think that Austin Rover is of assistance to either side on the question of safety in this case. It may be that some assistance can be derived from Lord Goff's speech on the subject of reasonable practicability, an expression which is used in section 4(2) and which must be taken to have the same meaning in any statute. I will return to that in due course.
76. Apart from the submission in respect of Nimmo, no attempt has been made to attack the correctness of Larner or its jurisprudential status. Larner is binding on this court and I am pleased that that is so because I respectfully agree with it. Further, if the safety of a place of work is to be judged objectively without reference to reasonable foresight of injury, it must follow a fortiori that it must be considered without reference to what society might at that time have thought was an acceptable degree of danger for employees to have to face.
77. It follows from this that I would hold that Judge Inglis erred when he adopted Rose J's formulation of the test of safety. It also follows that his consideration of whether the place of work was in fact made and kept safe must be revisited, applying the objective test without reference to reasonable foresight.
78. I would accept Mr Hendy's first submission that what is objectively safe cannot change with time. If 85dB(A)lepd causes deafness to a particular claimant, that claimant's place of work was not safe for him or her. It might have been safe for another person working alongside. But for the susceptible worker who has in fact been damaged, it can be demonstrated, without more, that his or her place of work was not safe. Looking at matters from the point of view of the work force generally, it is known that a minority of people will suffer appreciable harm as the result of prolonged exposure to 85dB(A)lepd. Therefore, it can be said that the place of work is not safe for the workforce because there is a risk of injury to all of them. Some of them will be injured but not all; no one knows which of them will not be injured. They all face some risk, save for those workers who are already known to be of average susceptibility. For those reasons, I would hold that, on the evidence before the judge, which was not controversial, the places of work where the ambient noise levels were 85dB(A)lepd or above were not safe.
79. That being my holding, Mr Hendy's alternative submission does not require consideration. But, if I were wrong about the irrelevance of reasonable foresight to the question of safety, I would accept his submission that, by the early 1970s, any employer who kept abreast of developing knowledge would have known that prolonged exposure to 85db(A)lepd was harmful to some people. So, he would have known that the place of work was unsafe for an undefined section of his workforce and that he must do what was reasonably practicable to make and keep it safe.
80. I turn to consider the question of reasonable practicability. The judge below did not consider this question because he held that the place of work was not unsafe. He did make some observations about the cost and difficulty of providing ear protection, which I have quoted at paragraph 42 above. He thought that such provision was neither expensive nor difficult. However, he did not consider all the factors which fall to be considered under reasonable practicability. I have considered whether the case should be remitted to the judge for consideration of this issue but the cost of so doing would be substantial. I consider that this court has the materials necessary to undertake the assessment. In so doing I will accept the judge's findings of primary fact and give appropriate weight to his inferences and opinions.
81. I begin by observing that the burden of proving what was reasonably practicable lies on the employers: see Nimmo.
82. The classic exposition of reasonable practicability is to be found in Asquith LJ's judgment in Edwards v National Coal Board [1949] 1 KB 704 CA at 712:

" 'Reasonably practicable' is a narrower term than 'physically possible' and seems to me to imply that a computation must be made by the owner in which the quantum of risk is placed on one scale and the sacrifice involved in the measures necessary for averting the risk (whether in money, time or trouble) is placed in the other, and that, if it be shown that there is a gross disproportion between them – the risk being insignificant in relation to the sacrifice – the defendants discharge the onus on them."

83. I note three matters in relation to that passage. First, it is clear that Asquith LJ was considering risks of which the employer was actually aware and was able to quantify. As a matter of common sense, if the employer does not know of the risk and cannot reasonably have been expected to know of it, it cannot be reasonably practicable for him to take any steps at all. If, on the other hand the employer ought to have known of the risk but did not and therefore never applied his mind to it, the burden on the employer, seeking to make out the defence, would be to show that it would not have been reasonably practicable for him to avoid or reduce the risk even if he had thought about it.
84. Second, Asquith LJ makes it plain that the balancing exercise is not done with a view to seeing whether the scales just tip. There must be a gross disproportion. There are dicta in Marshall v Gotham [1954] AC 360 which suggest that the defendant need show only that the test is simple disproportion. However, in Coltness Iron Co Ltd v Sharp [1938] AC 90, 94, Lord Atkin said in relation to the facts of that case that 'the time of non-protection is so short and the time, trouble and expense of any form of protection is so disproportionate, that I think the defence is made out'. It appears to me therefore that there must be at least a substantial disproportion before the defence will succeed.
85. Third, when Asquith LJ referred to the 'quantum of risk', he must have been referring to the gravity of the harm which might occur if the risk eventuated as well as the likelihood of it eventuating.
86. I mentioned earlier that there was a passage in Lord Goff's speech in Austin Rover relevant to reasonable practicability. This passage does not take matters any further but it does add the imprimatur of the House of Lords. After citing from Edwards v National Coal Board and Marshall v Gotham, Lord Goff said at page 626H:

"It follows from the passages which I have quoted that, for the purpose of considering whether the defendant has discharged the onus which rests upon him to establish that it was not reasonably practicable for him, in the circumstances, to eliminate the relevant risk, there has to be taken into account (inter alia) the likelihood of that risk eventuating. The degree of likelihood is an important element in the equation. It follows that the effect is to bring into play foreseeability in the sense of likelihood of the incidence of the relevant risk and that the likelihood of such risk eventuating has to be weighed against the means, including cost, necessary to eliminate it."

87. It appears therefore from the authorities that the process is well-established by which liability under section 29 is to be proved. First, the claimant must show that his place of work was not safe. If he achieves that, the burden passes to the employer to show that it was not reasonably practicable for him to eliminate the risk of harm. To avoid liability he has to show that the burden of eliminating the risk substantially outweighed the 'quantum of risk'. When that forensic process is compared and contrasted with the process by which liability at common law is established, it is hard to understand how lawyers and judges have so often fallen into the error of thinking that there is no significant difference between the two. That was the assumption upon which Rose J was working in Fazakerley and it is the effect of Judge Inglis's conclusion. In my view, that assumption or conclusion is clearly wrong.
88. At common law, the burden remains on the claimant throughout and he must show that the employer has failed to take reasonable care to avoid the risks of harm which he ought reasonably to have foreseen might arise in the circumstances. The hallmark of liability at common law is that the employer must be shown not to have acted reasonably. Reasonableness pervades the whole concept of common law liability. If the employer has acted reasonably, he will avoid common law liability. It might be reasonable for an employer to conclude that a particular risk is so slight or of such little consequence if it occurs that he can properly do nothing to eliminate or reduce it. He might reasonably decide to do nothing because a responsible body of professional or official opinion has suggested that the degree of risk in question is acceptable.
89. However, under the statute, the adjective 'reasonably' serves only to qualify the concept of practicability. Reasonableness of conduct does not stand as the hallmark by which statutory liability is avoided as it does at common law. The focus of the defence by which liability is avoided, once it has been shown that the place of work was unsafe, is practicability - qualified by reasonableness. Under the statute, the employer must first consider whether the employee's place of work is safe. If the place of work is not safe (even though the danger is not of grave injury or the risk very likely to occur) the employer's duty is to do what is reasonably practicable to eliminate it. Thus, once any risk has been identified, the approach must be to ask whether it is practicable to eliminate it and then, if it is, to consider whether, in the light of the quantum of the risk and the cost and difficulty of the steps to be taken to eliminate it, the employer can show that the cost and difficulty of the steps substantially outweigh the quantum of risk involved. I cannot see how or where the concept of an acceptable risk comes into the equation or balancing exercise. I cannot see why the fact that a responsible or official body has suggested that a particular level of risk is 'acceptable' should be relevant to what is reasonably practicable. In that respect, it appears to me that there is a significant difference between common law liability where a risk might reasonably be regarded as acceptable and statutory liability where the duty is to avoid any risk within the limits of reasonable practicability.
90. I turn to consider whether it was reasonably practicable for employers in the knitting industry, such as the defendants to these claims, to eliminate the risk of hearing loss from exposure to noise between 85 and 90dB(A)lepd.
91. I have said that it is not disputed that exposure to that level of noise was in fact harmful for a significant minority of employees. I have also said that it is not reasonably practicable for employers to take any steps to eliminate risks of which they are not and cannot be expected to be aware. It seems to me that, until the publication of the Code of Practice in 1972, there was no reason why employers in the knitting industry should have been concerned about the problem of noise. There is no evidence that, in that industry, there was any general awareness that longstanding employees became deaf. That is in contrast to other industries such as shipbuilding, heavy engineering and the weaving industry where, certainly from the early 20^th Century, everyone, employers and employees alike, knew that, if the employee worked in the noisy conditions for many years, he or she was likely to go deaf. The breakthrough which occurred in 1963, which was recognised by Mustill J in Thompson v Brown Shiprepairers [1984]QB 405 was that there was now something that could and should be done to protect the worker. But I do not think that 'Noise and the Worker' in 1963 would necessarily put on notice employers in an industry which had no traditional knowledge of deafness in its workforce.
92. However, I do think that all employers who had any noisy processes should have been aware of the 1972 Code of Practice within a short time, say a few months, of its publication. I include employers in the knitting industry who plainly did have noisy working areas. I am quite satisfied that an area where the ambient noise was 85dB(A)lepd would have seemed noisy to anyone entering it. Thus, I conclude that by say, mid-1973, employers such as these defendants should have been turning their minds to the problem of noise, using the Code of Practice as a guide.
93. Any of the respondents to this appeal would immediately have realised that they ought to measure the noise in their workshops. If they had done so, they would have discovered that they had some workshops in which the noise exceeded 90dB(A)lepd. They would have known that they ought to take steps in respect of the workers in those departments. If, as appears likely, there was little scope for reducing the noise at source, those employees would have had to be protected.
94. The respondents to this appeal would also have discovered that they had some workshops where the noise levels were less than 90dB(A)lepd but were in the range between 85 and 89dB(A)lepd. The department where Mrs Baker worked was one such. The Code of Practice told them that there was some risk to some employees but only those who were particularly susceptible. Thus, by the time that they had had the time and opportunity to measure their noise levels, which I would put at about mid-1974, employers in the knitting industry ought to have known that they had some workshops where the noise was such (85 to 89dB(A)lepd) that their place of work was unsafe for some (unidentified) employees and that the whole workforce in those departments was therefore at risk of harm. From that time, in respect of those workshops, (where the ambient noise was in the range 85-89dB(A)lepd) the employers were under a statutory duty to do what was reasonably practicable to eliminate the risk.
95. I appreciate that these employers probably did not realise, at least until the Court of Appeal decision in Evans v Sant [1975] 1QB 627 that section 29 of the Factories Act could be breached in respect of activities being carried on at the place of work as opposed to the physical characteristics of the place of work. However, ignorance of the law is no excuse or defence and an employer can be held liable for breach of a duty of which he was unaware.
96. So the forensic task for these employers was to show that, from mid-1974 (when they should have known that the noise levels in some departments were in the 85 to 89dB(A)lepd range and that such noise was likely to be harmful to some (albeit a minority) of the workers in those departments) it was not reasonably practicable for them to protect their workers from that risk of harm. It was plainly practicable; ear defenders of various kinds have been available from well before 1974. But was it reasonably practicable?
97. What are the factors which go into the balancing exercise? First, what was the quantum of risk? I explained at paragraph 23 above that there was, in the 1970s and possibly even today, some dispute as to the degree of risk arising from exposure to 85-89dB(A)lepd. However, Judge Inglis was able to estimate the quantum of risk in a general way without accepting or rejecting either side's statistical analysis of the NPL tables and other materials. He said:

"Above 85dB(A) the risk accelerates up to 90dB(A). In the high 80s, given long enough exposure, significant hearing loss may be expected in at least a substantial minority of individuals."

98. As I observed in paragraph 24 above it could not have been expected that a lay person would have had that understanding of the risk by 1974 but a suitably qualified expert would have done. Thus an employer who had asked a suitably qualified expert to advise him of the quantum of risk to his employees would have had a reply couched in terms of that sort. Assuming, as I do, that these employers well knew that some of their workforce stayed in their employment over many years (the claimants in this case were good examples), that advice would have conveyed to the employers that a substantial minority of their workforce in those departments were likely to suffer significant hearing loss. Faced with that advice, and given that there is no challenge to the judge's finding that the provision of ear protectors is neither difficult nor expensive, I cannot see how the employers could have hoped to establish that the burden of providing ear protectors was substantially disproportionate to the quantum of risk to their employees.
99. Was there any obligation on an employer to seek the advice of an expert in the assessment of the quantum of risk? Or would it have been sufficient for him to rely on the Code of Practice?
100. The respondents' argument is that the Code of Practice was sufficient and suitable advice and that it conveyed the message that an employer need not do anything to protect his workers from noise below 90dB(A)lepd; a responsible body or opinion considered that that was an acceptable degree of risk. Therefore, it was not reasonably practicable for the employer to provide ear protection for workers exposed to 85-89dB(A)lepd. As I understand it, the argument is that, until Government made it plain, by issuing regulations, that it was no longer considered acceptable to expose workers to that level of noise, the duty to protect did not arise at common law; nor was it reasonably practicable to provide protection. As I explained, an official view as to the acceptability of risk might well have a role to play in the determination of common law liability, where the standard is to do what is reasonable in the circumstances. But it has no part to play in the consideration of whether the burden of providing ear protectors is substantially disproportionate to the quantum of harm from exposure to noise in the range 85 to 89dB(A)lepd. Thus it has no part to play in the determination of whether it was reasonably practicable to provide protection.
101. I do not suggest that the content of the Code of Practice was irrelevant to the employer's assessment of the quantum of risk. However, it was, in itself, plainly inadequate as an assessment tool. It advised only that there was some risk to susceptible individuals from exposure below 90dB(A)lepd. It did not attempt to discuss the size of the minority which would be affected or the extent to which they would be affected. Further information was required for the purpose of an assessment of the quantum of risk over and above that which appeared in the Code itself. Expert advice was required for a proper assessment. The question to be asked of the expert would have been: how many of my workers in this workshop are likely to be affected by the noise and how severely? I accept that until the publication of the British Standard BS 5330 in July 1976, it was not easy to assess the quantum of risk from noise in the 85 to 90dB(A)lepd range. No doubt there were academics at the University of Southampton who could have done so from about 1970 but I accept that this might not have been within the grasp of the 'ordinary' acoustic engineer. However, from July 1976, there was a method available which could be used by anyone with a modest degree of mathematical skill. Certainly any consultant acoustic engineer could have used the British Standard method. Accordingly, I conclude that by late 1976 or early 1977, the average-sized employer in the knitting industry could and should have been able to make an informed assessment of the quantum of risk arising from the below 90dB(A)lepd noise in his workshops. As I have said above, this assessment would have led to the employer to broadly the same conclusion as was reached by Judge Inglis. Once that assessment had been made, it could not in my judgment be said that it was not reasonably practicable to provide ear protectors.
102. Accordingly, I am of the view that, from early 1977, Quantum (and indeed any other employer of average size in the knitting industry) who exposed his employees to 85dB(A)lepd or more without protection was in breach of its duty under section 29 of the Factories Act. I would allow about 6 to 9 months for the provision of ear protectors once the decision had been taken that they should be provided. For the sake of simplicity, I would fix the date by which action should have been taken as January 1978.
103. It follows that I would allow this appeal and hold Quantum Clothing Ltd liable for the damage to Mrs Baker's hearing attributable to her unprotected exposure from 1 January 1978. As I have earlier explained, it is common ground that any apportionment should be made on a time basis. Mrs Baker was exposed from 1971 until 1989, a period of 18 years. The exposure in breach of duty was for about 12 years. Thus I would award damages of 66.67% of £5,000 which is £3,334.
104. My conclusion in respect of section 29 effectively disposes of all issues in the appeal. All the respondents were or would be liable from January 1978. Thus the issues arising under common law liability and the differences between the positions of the respondents based upon their actual knowledge have become academic. For that reason, I propose to deal with those issues very briefly indeed.
105. As I have explained above, I consider that the opinion, implied by the Code of Practice, that exposure to noise below 90dB(A)lepd was 'acceptable' was a factor which could properly be taken into account when an employer considered what it was reasonable for him to do in respect of the health and safety of his employees. In short, I take the view that Judge Inglis's holding which I quoted at paragraph 46 cannot be faulted. I would uphold his view that there was no breach of the duty at common law during the period for which a responsible body of opinion regarded it as 'acceptable' to expose employees to noise in the 85-89dB(A)lepd range. I consider that, for the employer with the ordinary or average degree of knowledge, the judge's conclusion that that period came to an end in 1987, following publication of the second European draft directive, was a reasonable conclusion, although, left to myself, I would have said that the publication of the first draft directive in 1982 would have put all employers on notice that it could no longer be regarded as acceptable or reasonable to leave this group of employees exposed.
106. The judge allowed a further two years for the implementation of the hearing protection policy following the date on which the employer should have realised that it owed a duty to protect these groups of employees. It appears that the judge was allowing time not merely for the provision of ear protectors but also for the noise measurement and policy decisions which preceded the actual provision of protection. I think that, if employers were to be given until 1987 to appreciate that workers exposed to noise below 90dB(A)lepd ought to be protected, they must by that time be taken to have known already to which workshops that applied. Consequently, I think that a further two years is too generous and do not think that any more than a further 6 to 9 months could be justified. That is the period that I allowed for actual provision in my own decision at paragraph 102. In case it should ever become material, I would fix the date for breach of common law duty for the average employer at January 1988.
107. The judge imposed different dates of common law liability on Courtaulds and Pretty Polly from that of Quantum and Guy Warwick which he regarded as having only an average degree of knowledge. It is clear that from 1972 all employers should have been aware of the risk to some of their employees from exposure to 85-89dB(A)lepd. The question at common law was when they should have realised that it was no longer to be regarded as acceptable to disregard that risk. The judge's conclusion in respect of Courtaulds was plainly justified. They actively opposed the proposal in the first draft directive, not on the ground that the risk was minimal but on the ground that the cost to them would be too great. By early 1983, they could no longer have thought that a responsible body of opinion took the view that it was acceptable to ignore the risks of harm below 90dB(A)lepd. They should by that time have known which of their workers required protection and only a further 6 to 9 months should be allowed for provision.
108. Pretty Polly was in a different position in that there was no direct evidence that it knew of the first draft directive. However, in my view the judge was entitled to hold that it must have done. In any event, there was other evidence that it had been advised of the need to taken action in respect of the lower levels of noise. In my view, the judge's holding was justified, subject to the reduction in the period allowed for provision.
109. As a fall-back submission, Mr Hendy argued that the judge had been wrong to reach a different conclusion in respect of Quantum. There was evidence that it was aware of the first draft directive (see paragraph 37 above) and Mr Hendy submitted that, given that knowledge, it was irrational to say that, because the group was smaller than Pretty Polly or Courtaulds and operated as individual companies without the benefit of central advice on health and safety issues, they should be treated differently from the other two employers. I would accept that submission and would hold that, if it were to become material, Quantum would have been in breach of its common law duty at the same date as Courtaulds.
110. Accordingly, for the reasons I have given, I would allow the appeal of Mrs Baker and would award her damages in the sum of £3,334.

Lord Justice Jacob

111. I have read both judgments in draft. I agree with both and have nothing to add.

Lord Justice Sedley

112. I agree that there is liability in this case under s.29 of the Factories Act 1961. I do not dissent from the notional date for the inception of liability proposed by Smith LJ. I also agree that the judge's finding that there was no parallel liability at common law is tenable.
113. For reasons fully explained by Smith LJ, the fact that in the run of personal injury cases the two kinds of liability stand or fall together does not mean that the statute merely replicates the common law. It means that in most cases the risk is known and the question is whether it was reasonable and practicable to do more than was done to guard against it.
114. In a case such as the present, by contrast, the risk is real but not known to the employer. The workplace is therefore unsafe; but it does not follow that it is not reasonably practicable to do something about it. If the risk is unascertainable that will be so; but not where, as here, it can and should be ascertained and, once ascertained, can be readily guarded against. In such a case the onus on the employer has not been discharged. This was precisely the policy of s.29.