England and Wales Court of Appeal (Civil Division) Decisions

IN THE COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM Liverpool County Court
His Honour Judge Gore QC
2011/PI/10849

		Royal Courts of Justice Strand, London, WC2A 2LL
		29/07/2011

Lord Justice Hughes :

1. On 17 June 2008 a Mr Mooney complained to the police in Liverpool that he had been assaulted in the street 4 days earlier by Mr Hayes. He made a written statement. He said that the assault was because he had in the past bought cocaine from Hayes, and that Hayes was claiming that he owed him money. He said that Hayes had previously threatened and harassed him by text messages and telephone calls in pursuit of money, and that the demands had included threats to kidnap him. On 13^th June, according to Mooney, Hayes had confronted him in the street at about 1130 in the morning when he (Mooney) was shopping with his mother and sister. Hayes was said to have seized Mooney by the throat, rifled through a bag he was carrying, demanded money and threatened greater violence if he did not get it. Moreover, he was said afterwards to have telephoned him to repeat the threats, saying, according to Mooney, "You're lucky I'm not still living at my Mum's; I should have sent some lads round to your house ages ago."
2. Although the offence actually committed was treated, it appears, as the relatively minor one of common assault, this was, if true, quite a serious allegation of strong arm tactics in the street by a drug dealer against a drug user. The statement went on to say that Mooney was 'scared' by Hayes. He avoided going out, and when he did he was told by others that Hayes was looking for him. There had been family discussions about whether or not to tell the police, with one parent saying yes and the other saying no.
3. A few days later on 24 June, the police station which had received and logged the complaint sent an E-mail to the Birkenhead tactical team "to assist in effecting arrest". At some point the case was allocated to PC Priestley to deal with. He was at the time a probationary constable operating under the tutorship of PC Jones, an experienced officer who has subsequently assumed the role of Acting Sergeant. The constables would, of course, have had other cases and other duties also. So far as this one was concerned, Mr Priestley planned to locate Mr Hayes.
4. He tried to find him via his mother, with whom Hayes indeed did not, it appears, live. It seems that in due course his mother either provided a telephone number and/or warned Hayes that the police were trying to speak to him. As a result, when PC Priestley came on duty on the evening of 26 June at 2100, he was able to speak to Hayes on the telephone. The constable said he needed to see Hayes. Hayes did not make difficulty and agreed to meet the constable not far from where he was living, at Lime St railway station. There he met PC Priestley, who was with other officers, one of whom was his tutor PC Jones. The judge found that Hayes was thereupon arrested, and duly told of the accusation against him, including its date, time and place. There is (now) no challenge by Mr Hayes to those findings of the judge.
5. Mr Hayes was taken in a police car to St Anne's police station. He was duly received by the custody sergeant, Sgt Minnery, who recorded the time as 2233. Sgt Minnery approved the detention. When given the option, Hayes perfectly sensibly elected to be attended by the duty solicitor, who was not immediately available, and indeed did not arrive before he was released about two and a half hours later. He nominated a friend to be told of his arrest and was placed in a cell.
6. PC Priestley then spoke on the telephone to the complainant, Mr Mooney, to tell him of the arrest. Thus to keep a complainant informed would no doubt be good practice. Mooney told him that he did not wish to pursue the complaint. That is of course by no means unusual. There are many possible reasons for it being said, only one of which is that the original complaint is admitted to be false. Mooney did not say that was the reason. He did say that he was anxious to know (a) how long Hayes would be in custody and (b) whether he would know that it was Mooney who had complained. Thus, so far as the apparent facts known to PC Priestley went, it was a distinct possibility that the complaint was true but Mooney did not now want the exposure of pursuing it. If it were true that Hayes was or had been a drug supplier to Mooney, it would not be at all surprising that an erstwhile customer would prefer not to be known on the streets to be giving evidence for the prosecution against him. Moreover, Hayes had apparently had quite a lot of notice that the police wanted to speak to him and thus, if the original allegation and its circumstances were true, might well have had the opportunity to let Mooney know that it would not be in his interests to pursue his complaint; the evidence of the constable was that he was concerned that this might be what had happened. Decisions as to whether criminal allegations are or are not to be pursued are of course not for the private resolution of the complainant, but are for the police and/or Crown Prosecution Service.
7. PC Priestley resolved to go to see Mooney. Before he left, he told Sgt Minnery, at least in general terms, that the complainant was speaking of withdrawing the complaint, and that he was going to see him.
8. PC Priestley visited Mooney there and then, somewhere around 2330. He spoke to him for about an hour. Mooney remained clear that he did not wish to pursue the complaint and PC Priestley took from him a statement which he described as 'a retraction statement'. What it actually said was:

"I would like to retract my statement of complaint. I will not assist the police with their investigation. I will not attend court with regard to this matter."

It did not say that the original allegation was false.

9. When PC Priestley got back to the police station with this document, Sergeant Minnery looked at it and determined that Hayes should not be charged and should be released. That was at 0058. He was sleeping in the cell as he had been for the past two hours or thereabouts. He was accordingly awakened and released.
10. Thus far the facts are clear and uncontroversial.
11. Mr Hayes sued the Chief Constable for wrongful arrest and unlawful detention. The judge found for the defendant chief constable. Two points are taken here against that decision:

i) the original arrest was unlawful because, it is said, PC Priestley did not actively consider all possible alternatives to arrest but simply formed the view arrest was necessary; and

ii) in any event, the detention became unlawful once the custody sergeant was informed that the complainant Mooney did not wish to pursue the allegation, as he was before PC Priestley went to Mooney's home to speak to him.

The statutory power of arrest

12. Prior to 2005 the constable's power of arrest depended upon either the offence being an arrestable offence within section 24 Police and Criminal Evidence Act 1984 (generally one carrying punishment of five years' imprisonment or greater) or, for other offences, the general arrest conditions provided by section 25 being applicable. For an arrestable offence, the power to arrest existed (inter alia) when the constable had reasonable grounds for suspecting (i) that it had been committed and (ii) that the person in question was guilty of it: section 24(6) as it then stood. For other offences, the general arrest conditions permitted arrest, broadly, either when the suspect's name and address could not readily be ascertained or when the constable had reasonable grounds for believing arrest to be necessary to prevent the suspect causing harm or damage, or in certain other specified consequences.
13. In that state of the law, for an arrestable offence, the only formal condition for summary arrest was that the constable had reasonable grounds for suspecting that it had been committed and that the suspect had committed it. There was no statutory condition of belief that arrest was necessary. It was well recognised, however, that even if this double condition was met, not every case justified an arrest. The constable had a discretion which he had to exercise. If he exercised it in a manner which was Wednesbury unreasonable, the arrest would be unlawful. Thus there were three stages to the justification of an arrest. Woolf LJ set them out in Castorina v Chief Constable of Surrey [1996] LGR 241 as follows:

"(1) Did the arresting officer suspect that the person who was arrested was guilty of the offence ? The answer to this question depends entirely on the findings of fact as to the officer's state of mind.

(2) Assuming that the officer had the necessary suspicion, was there reasonable cause for that suspicion ? This is a purely objective requirement to be determined by the judge, if necessary on facts found by the jury.

(3) If the answer to the two previous questions is in the affirmative then the officer has a discretion which entitles him to make an arrest and in relation to that discretion has been exercised (sic) in accordance with the principles laid down by Lord Greene MR in Associated Provincial Picture House v Wednesbury Corporation."

14. The Serious Organised Crime and Police Act 2005 amended the 1984 Act by substituting a new s 24 and repealing s 25. The broad effect is to create a single code of arrest powers which is applicable to all offences; the legal concept of an arrestable offence disappears. Section 24 Police and Criminal Evidence Act 1984 now provides the same condition for arrest without a warrant (a) for all types of offence and (b) for cases of known or suspected offences being committed or about to be committed (subsection (1)), suspected past offences (subsection (2)), and known past offences (subsection (3)). For all of these categories, the condition is as follows:

"24(4) But the power of summary arrest conferred by subsection (1), (2) or (3) is exercisable only if the constable has reasonable grounds for believing that for any of the reasons mentioned in subsection (5) it is necessary to arrest the person in question."

Subsection (5) then sets out exhaustively the reasons for which it can be judged necessary to arrest a suspect. The first four reasons derive substantially from the old general conditions previously contained in section 25. Subsection 24(5)(e) is new:

"(e) to allow the prompt and effective investigation of the offence or of the conduct of the person in question."

There is also a new reason (f) which is not relevant to the present case.

15. The effect of this is, in one sense, to tighten up the accountability of police officers, at least in the case of arrest for serious offences, because those arrests now become subject to the criterion of necessity, whereas previously only non-arrestable offences were. As Toulson LJ pointed out in this court in Shields v Chief Constable of Merseyside Police [2010] EWCA Civ 1281, the new formulation also (a) creates a single code for all offences, (b) ensures conformity with Article 5 ECHR and (c) incorporates the Wednesbury principle of review via the concept of reasonable grounds, brought forward from the previous law and extended to the new general requirement of necessity.
16. In the present case, PC Priestley, the arresting officer, relied upon subsection 24(5)(e). It is common ground that it is for the police to justify an arrest. It follows that the police had to show two things:

(i) that PC Priestley had reasonable grounds for suspecting that an offence had been committed and that Mr Hayes was guilty of it: S 24(2); and

(ii) that he had reasonable grounds for believing that it was necessary to arrest him to allow the prompt and effective investigation of the offence or of the conduct of Mr Hayes: s 24(4) and (5)(e).

17. There is now no dispute that condition (i) was met. The original witness statement of Mr Mooney provided reasonable grounds to PC Priestley for suspecting both that an offence had been committed and that it was Mr Hayes who had committed it. The contentious issue is condition (ii).
18. It is the contention of Mr Blaxland QC, for Mr Hayes, that the effect of section 24(4) is that in order to justify the arrest, it must be shown that the arresting officer passed through three stages of a thought process:

(a) he must apply his mind to section 26(4) and (5), that is to say he must understand that he must believe arrest to be necessary for one of the specified reasons and he must in fact believe this; and

(b) he must actively consider all possible courses of action alternative to arrest; he must have taken into account all relevant considerations and have excluded all irrelevant ones; and

(c) he must make a decision which a constable acting reasonably could have reached.

19. Mr Blaxland accepts that PC Priestley passed through stage (a). He submits, however, that the second stage could not be shown to have been passed. The suspect was co-operative. It would, it is said, have been equally effective to invite him to the police station for voluntary interview. If the police needed to see any mobile telephone which he might have, as potential evidence in a case where the complainant said he had been threatened by text and telephone messages sent by the suspect, it would have been just as effective to have asked him to bring his mobile telephone to the rendezvous and to invite him to hand it over. Resort to arrest could and should have been left unless and until he either failed to co-operate by being interviewed or failed to hand over any telephone he had. The officer, he submits, simply did not apply his mind to the alternatives to arrest which were available.
20. It is the second stage in this thought process which is contentious. Mr Beer QC, for the Chief Constable, submits that it is not to be found in the Act, is unnecessary, and would mean that the decision of the constable on the spot, often in difficult circumstances, would have to survive what is in effect a public law reasons challenge.
21. Mr Beer submits that what must be shown is:

(i) that the constable actually believed that arrest was necessary, and for a subsection (5) reason; and

(ii) that objectively that belief was reasonable.

He accepts that even if a constable believes arrest to be necessary, there remains a discretion not to carry it out, but he contends that except for this residual situation the concept of discretion, which was previously a distinct stage in the legality of arrest, is for all material purposes subsumed within the new statutory test.

22. It is accepted on both sides, in accordance with longstanding authority, that in answering whatever are the right questions, the court is concerned with the facts as known to the officer making the arrest. Circumstances unknown to the arresting officer which, if known to him, would have provided reasonable grounds for believing arrest to be necessary, cannot be relied upon. See, amongst other cases, Dallison v Caffrey [1965] 1 QB 348 at 371E and O'Hara v Chief Constable of RUC [1997] AC 286 at 298A per Lord Hope.
23. Accordingly the question before us boils down to whether Mr Blaxland's suggested second stage thought process (see paragraph [18] above) must be shown to have been passed through. Before an arresting officer can show that he reasonably believed that arrest was necessary for a subsection (5) reason, must he actively have considered every possible alternative to arrest, and must he have considered every factor which is relevant, and disregarded every factor which is irrelevant to the issue, or is it enough that he bona fide believed arrest to be necessary, for an identified subsection (5) reason, and that objectively that belief was reasonable ?

The evidence in this case

24. It is far from clear that this question genuinely arises in this case. The suggestion that it does derives from skilful cross examination of the arresting officer by Ms Hemingway. She had elicited from the officer that Mr Hayes had co-operated by turning up to the rendezvous at the railway station and had given no reason to think that he would abscond or fail to comply with the interview which the constable intended to conduct. The questioning proceeded:

"Q: Do you agree that to ask him voluntarily to attend at the police station would have been a less intrusive way of dealing with Mr Hayes ?

A: No, your Honour.

….

Q: Well, if he had voluntarily attended he wouldn't necessarily have been arrested, would he ?

A: No, your Honour, at that time my intention was to arrest the defendant, your Honour.

Q: But you had the option not to arrest him ?

A: Not in this instance, your Honour, no.

Q: So you didn't turn your mind at all to a situation where you might not have to arrest him ?

A: No your Honour."

A little later in the same passage there occurred the following question and answer:

"Q: You gave no thought at all to him voluntarily attending at the police station to answer questions ?

A: No your Honour."

25. Although the officer thus assented to the propositions that he had not turned his mind to an alternative to arrest, and had given no thought to voluntary attendance, these answers need to be read in context. The officer had previously said, perfectly clearly, that he arrested the suspect because, unless he did, (a) he had no power to detain him for questioning, (b) he had no power to seize his telephone and (c) he would have had no power to prevent the suspect from immediately sending an unsupervised call or message on his telephone. Immediately after assenting to the suggestion that he had not turned his mind to voluntary attendance, the officer gave this evidence:

"Q: So that would have been less intrusive in terms of restriction on his liberty ?

A: It would have, your Honour, but I believed it would have hampered my investigation."

26. It was one of the difficulties of this case that the statements of all the relevant witnesses, Hayes and the three police officers, were not made until just under two years after the event. So far as PC Priestley and PC Jones were concerned, they told the Judge that they had little independent recollection of the case. They, and especially Mr Jones, relied significantly on their usual practice for what had occurred. The evidence just cited seems to me fairly clearly to suggest that when the officer agreed that he gave no thought to, or did not turn his mind to, voluntary attendance, what he really meant was that he had considered it but had summarily rejected it. That is why he said that voluntary attendance would have been less intrusive, but he thought it would have hampered his investigation. Mr Beer suggested that this is what the judge found. It may be so, but that is not by any means clear. The judge said this:

"[35] In my judgment, despite the fact that PC Priestley said in evidence to me that he did not consider the alternatives and despite the fact that there were alternatives available, namely the voluntary attendance at the police station for the purpose of interview, in my judgment the decision was within the range of choices from which he was entitled to choose and his decision was therefore lawful…..

…..

[36]…….I do not understand the logic of reliance on the lack of consideration of other options by PC Priestley as evidence of lack of justification for arrest. Clearly PC Priestley subjectively believed in the necessity, which is why it was the only option that he considered."

27. Although I have no doubt that it was open to the judge on the evidence he had heard to have found that PC Priestley did indeed consider voluntary attendance, but rejected it summarily, those observations are at least as consistent, and perhaps more consistent, with the judge taking the view that what was required was simply subjective belief in necessity plus objective justification, so that it was unnecessary to decide whether the constable had actually considered and rejected voluntary attendance.
28. PC Priestley's tutor, PC Jones, gave evidence which the judge found impressive. It included the assertion that:

"….due to the nature of the text calls and the kidnaps we did discuss voluntary attending and what could happen and we decided the most proportionate way to deal with it was by arrest."

Mr Jones also gave additional reasons why non-arrest was not appropriate and arrest was necessary. First, given the apparent complaint of threats to the complainant Mooney, it would be likely to be necessary when Hayes was released, after confronting him with Mooney's complaint, to protect Mooney by imposing bail conditions designed to prevent contact between the two. That could not be done unless Hayes had been arrested. Secondly, the officers had no address for Hayes: he did not live with his mother.

29. If there were a finding of fact that tutor and pupil had considered voluntary attendance and rejected it for the reasons given by each of them, the issue raised in this appeal on Mr Hayes' behalf simply would not arise, for the arresting officer would indeed have considered non-arrest and rejected it on the grounds that arrest was necessary for prompt and effective investigation to be made (subsection (5)(e)). Mr Beer rightly reminds us that the judge described PC Jones as a compelling and impressive witness.
    The judge went on to rely on the reasons which Mr Jones had given for the necessity of the arrest. There is, however, no express acceptance of his evidence that he and PC Priestley had discussed non-arrest. It seems to me at least likely that that is for the same reason that there is no express finding that PC Priestley did consider, but rejected, voluntary attendance: that is to say the judge did not think it necessary to say that that was his finding. He did not think that the question arose, because he did not consider that Mr Blaxland's second stage thought process had to be demonstrated.

The correct test for arrest

30. Section 24 of the Act does not clearly impose a requirement for Mr Blaxland's second stage thought-process. It requires that the officer have reasonable grounds for believing that it is necessary, on one of the statutory grounds, to arrest. I agree, as is common ground, that on authority that means that he must in fact believe it. But as a matter of construction, it might mean either what Mr Blaxland suggests, namely that the second stage thought-process must be demonstrated, or what Mr Beer suggests, namely that it calls simply for honest actual belief, objectively justified as reasonable on the facts known to the officer.
31. In Alexander and others [2009] NIQB 20 the Divisional Court of the Queen's Bench Division in Northern Ireland considered four applications for judicial review in which the applicants contended that they had been arrested unlawfully. The applications for judicial review were misconceived because there was a perfectly adequate remedy, if an arrest were unlawful, in an ordinary action for wrongful arrest. In all but one of the cases the court did not, for this reason, address the merits of the application at all. However, it did make some general observations upon the import of the Northern Ireland equivalent of section 24 Police and Criminal Evidence Act, which is to be found in identical terms in Article 28 of the Criminal Evidence (Northern Ireland) Order 1989, as amended.
32. The court concluded, as is common ground before us, that the validity of arrest depends on what was in the mind of the arresting officer: see above at paragraph [22]. Next, it considered and rejected the submission that the requirement for necessity of arrest meant that there must be no feasible or viable alternative or that arrest must in every case be a matter of last resort. Rather, it held, it meant that arrest must be believed (on reasonable grounds) to be "the practical and sensible option" (paragraph [18]). It also considered and rejected the submission that in order to have reasonable grounds for believing arrest to be necessary, the officer must interrogate the suspect as to whether he will attend the police station voluntarily. Sir Brian Kerr CJ (as he then was) expressed the position in these terms at paragraph [19]:

"Given the scope of the decision available to a constable contemplating arrest, we do not consider that it is necessary that he interrogate a person as to whether he will attend a police station voluntarily. But he must, in our judgment, at least consider whether having a suspect attend in this way is a practical alternative. The decision whether a particular course is necessary involves, we believe, at least some thought about the different options. In many instances this will require no more than a cursory consideration, but it is difficult to envisage how it could be said that a constable has reasonable grounds for believing it necessary to arrest if he does not make at least some evaluation as to whether voluntary attendance would achieve the objective that he wishes to secure."

33. Mr Blaxland invites us to say that this carries the implication that his second-stage thought-process is a requirement of the law. He draws attention to an earlier sentence in the judgment, at paragraph [16] where there is a reference to the constable having to take into account all obviously relevant circumstances.
34. That, however, would be to subject the process of arrest to the rigour of a public law reasons challenge. That this is not what the court in Alexander had in mind is clearly demonstrated: the thought-process was aptly described as 'at least consider', and 'a cursory consideration' was held to suffice. The correct analysis is contained in the last four lines of passage cited above. The relevance of the thought process is not that a self-direction on all material matters and all possible alternatives is a pre-condition to legality of arrest. Rather it is that the officer who has given no thought to alternatives to arrest is exposed to the plain risk of being found by a court to have had, objectively, no reasonable grounds for his belief that arrest was necessary. In the single case whose merits were considered (Farrelly) this was precisely the reasoning of the court. The officer in that case had adopted a pre-determined decision to arrest and had not thought about any alternative. The court held that he had not, objectively viewed, had reasonable grounds for his belief that arrest was necessary: see paragraph [24].
35. We were referred also to the first instance decision in Richardson v Chief Constable of the West Midlands [2011] EWHC 773 (QB). There, a schoolteacher had been accused by a pupil of an assault, which he denied. The pupil and his parents had since abandoned any wish to pursue the matter. The case had been reported to the police. Consistently with his denial, the teacher declined to be dealt with under an internal procedure which took effect in similar manner to a police caution, because it was predicated on an admission, which he could not make and which would be very damaging to his career. Saying that that was his stance, the teacher attended voluntarily with his solicitor ready to be interviewed, but was arrested. The solicitor told the policewoman that there was in his view no need for arrest, and that the teacher would co-operate with any interview, but, without reason being given, the arrest was nevertheless made. The arresting officer did not give evidence and there was thus no evidence from her of what her reasons may have been for making the arrest; the only material available was that she had told the custody sergeant that it was to allow prompt and effective questioning. The custody sergeant's own decision for accepting detention was made without knowing that the teacher had attended two different police stations voluntarily. Slade J applied Alexander for the meaning of necessity being that arrest was the practical and sensible option. She referred to the passage in Alexander which I have set out at paragraph [32] above. The critical question was said to be whether the officer had reasonable grounds for believing arrest to be necessary; it is apparent that the judge simply applied an objective test to that question without needing to consider whether the more exacting test suggested by Mr Blaxland in the present case was necessary. She held, if I may so say unsurprisingly, that "There is simply no evidence as to whether and if so why PC Downie considered it necessary to arrest the claimant", and that a decision that the teacher's arrest was necessary was Wednesbury unreasonable. That amounts to a conclusion that there were, objectively judged, no reasonable grounds for such a decision and is entirely consistent with the approach for which Mr Beer contends, and which I believe to be correct.
36. That approach is also consistent with the prior law on the concept of necessity in this context, to which the court in Alexander was not, so far as I can see, referred. Under the prior law, necessity was a statutory condition where some (but not all) of the general arrest conditions of the old section 25 applied. But it was also (and remains) a condition applicable to legality of the custody sergeant's decision as to continued detention. Section 37, which is unaltered by the amendments, provides that if the custody officer does not, after time for consideration, have enough evidence to justify charging the suspect, he must release him:

"unless the custody officer has reasonable grounds for believing that his detention without being charged is necessary to secure or preserve evidence….or to obtain such evidence by questioning him."

As can be seen, this provision is couched in exactly the same form of reasonable grounds for believing in necessity as is the modern section 24(4) which we have to consider. In Wilding v Chief Constable of Lancashire (22 May 1995) this court held (i) that attempts to define, or to provide synonyms for, 'necessary' should be avoided and (ii) that in asking whether further detention was lawful or unlawful the court should ask itself whether the decision of the custody sergeant was unreasonable in the sense that no custody officer, acquainted with the ordinary use of language and applying his common sense to the competing considerations before him, could reasonably have reached that decision. I agree that Parliament must, on ordinary principles of statutory construction, be taken to have assumed this state of the law in adopting the same formulation in the new section 24(4). That is consistent with Mr Beer's formulation of the test, and not with Mr Blaxland's.

37. Mr Blaxland referred us also to Code of Practice G, which deals with the statutory power of arrest. It contains the following statements:

"1.3 The use of the power must be fully justified and officers exercising the power should consider if the necessary objectives can be met by other, less intrusive means. Arrest must never be used simply because it can be used. Absence of justification…may lead to challenges should the case proceed to court…."

38. Like comparable codes of practice, this one is issued by the Secretary of State under section 66 of the Police and Criminal Evidence Act 1984: see section 66(1)(a)(iii). Its legal effect is stated in section 67(10) and (11). A failure by a police constable to comply with any provision of the code does not by itself render him liable to any criminal or civil proceedings. However, in any court proceedings, criminal or civil, the code is admissible in evidence, and if its provisions appear to be relevant to any question arising, it is to be taken into account in determining that question.
39. Code G 1.3, quoted above, thus cannot create the rule for which Mr Blaxland contends. Nor do I think that it can be said to assume any such rule. It is perfectly consistent with the construction of the Act for which Mr Beer contends. The officer ought to apply his mind to alternatives short of arrest, and if he does not do so he is open to challenge. The code provides a sensible warning to that effect. But the challenge, if it comes, is not one which requires the officer's decision to be subjected to a full-blown public law reasons challenge. It is one which requires it to be shown that on the information known to the officer he had reasonable grounds for believing arrest to be necessary, for an identified section 24(5) reason.
40. That also seems to me to be clearly the conclusion which best represents the balance which the law must strike in this area between practicable policing and the preservation of the liberty of the subject. The circumstances of the present arrest were comparatively relaxed. It is by no means always so. To require of a policeman that he pass through particular thought processes each time he considers an arrest, and in all circumstances no matter what urgency or danger may attend the decision, and to subject that decision to the test of whether he has considered every material matter and excluded every immaterial matter, is to impose an unrealistic and unattainable burden. Nor is it necessary. The liberty of the subject is amply safeguarded if the rule is as Mr Beer contends, namely (1) the policeman must honestly believe that arrest is necessary, for one or more identified section 24(5) reasons, and (2) his decision must be one which, objectively reviewed afterwards according to the information known to him at the time, is held to have been made on reasonable grounds. Mr Blaxland realistically accepted that if that is the law, no suspect suffers any injury. That was the way Lord Hope expressed the prior law of arrest for an arrestable offence in O'Hara v Chief Constable of the RUC [1997] AC 286 at 297H:

"The protection of the subject lies in the nature of the test which has to be applied in order to determine whether the requirement that there be reasonable grounds for the belief is satisfied."

41. I should add that we have not been concerned in the present case with the position of an arresting officer who, often in a complex enquiry, receives an order to arrest a particular suspect. Such an officer will often not have access to all the material which the officers directing the enquiry will have. The decision to arrest, and to do so at a particular time, will often be part of a closely co-ordinated plan for the enquiry. I pause only to say that it is clear from O'Hara v Chief Constable of the RUC that this common situation is readily accommodated within the rules as I have set them out to be. The arresting officer must himself have reasonable grounds for believing that the suspect has committed an offence, and likewise reasonable grounds for believing that it is necessary, for a section 24(5) reason or reasons, to arrest him. But information given by others, attached to orders issued by them, can be and usually will be part of the information which goes to his grounds for belief of one or both matters, and thus to the reasonableness of the belief. That that is the law provides another reason why section 24(4) ought to be interpreted in the manner stated, rather than as requiring comprehensive consideration by the officer of all matters capable of being relevant to the decision, which would require him to have access to, and time to digest, a much fuller picture of the overall investigation than is realistic.
42. Accordingly I have no doubt that the correct test is Mr Beer's two stage test, rather than Mr Blaxland's three stage one (see paragraphs [18] and [21] above). Assuming that the judge applied this two stage test, his conclusion that the arrest was lawful is unassailable. Whilst of course it may be that it is quite unnecessary to arrest a suspect who will voluntarily attend an interview, as it was with the schoolteacher in Richardson, it is not the case that a voluntary attendance is always as effective a form of investigation as interview after arrest. Section 29 of the Act reminds officers of their duty, if inviting voluntary attendance, to tell the suspect that he may leave at any time he chooses. It would not be honest for an officer to invite a person to attend a voluntary interview if he intended to arrest him the moment he elected to leave. Nor would it be effective. It would mean that the suspect could interrupt the questioning the moment it reached a topic he found difficult. Even if it were possible simply then to arrest him, the interview could not continue until all the important formalities of reception into custody, checks on health, notification of friends or relatives and so on had been complied with. If the complaint made by Mr Mooney was true and the suspect was a drug dealer manipulating his customer, this was a case where that might happen. Moreover, the officer did need to inspect any mobile telephone which the suspect might have, and without warning him of the intention; the suggestion that he ought to have been asked politely to bring his telephone with him would, assuming a truthful complaint, have accomplished nothing other than the deletion of all relevant information or the leaving of the phone behind. Thirdly, the officer did need to be able to frustrate any attempt, if it were made, to send an unsupervised message on arrest, which might, assuming the complaint to be true, easily involve getting someone else to visit the complainant to deter him. I also agree that it was very likely, if the investigation proceeded, that the suspect would have to be released on bail conditions designed to prevent contact with the complainant; whether this can properly go to necessity on ground 24(5)(e) or would have to call for separate invocation of ground 24(5)(d) ("to protect a….vulnerable person from the [suspect]") is a question on which we have not heard argument and which we do not need not resolve.
43. If necessary, I would also conclude that if the correct test were Mr Blaxland's three stage one, the judge could only have held, on the facts he found and the state of the evidence described in paragraphs [24] to [29] above, that he had indeed considered with Mr Jones the alternative of voluntary attendance and had summarily rejected it on reasonable grounds. This is, however, unnecessary given the view I take of the correct test.

Continued detention

44. The custody sergeant is under a duty to release Mr Hayes if at any time he "becomes aware….that the grounds for …detention…have ceased to apply": section 34(2)(a). Similarly, since what is in question is detention before charge, the sergeant must release him unless "he has reasonable grounds for believing that his detention without being charged is necessary to secure or preserve evidence….or to obtain such evidence by questioning him."
45. I am afraid that I regard it as simply unarguable that merely because Mr Mooney had, on Mr Priestley's initial telephone call, said that he wished to withdraw his complaint, that by itself meant that there were no longer grounds to detain Mr Hayes for interview. On the contrary, given the type of complaint and the relationship between the parties if it was true, it seems to me that any responsible officer would wish first to check with Mr Mooney (a) that it was indeed him on the telephone and (b) that he had come under no pressure. Mr Priestley went out to do this straight away. There were without doubt reasonable grounds to detain Mr Hayes for the short time which it took to do so. Wilding (supra at paragraph [36]) was a less strong case in which a decision to continue detention whilst a brief enquiry was made of the complainant was held to be made on reasonable grounds, and in the absence of any suggestion of a danger of interference with the complainant.

Conclusion

46. For these reasons I would dismiss the appeal.

Lord Justice Richards:

47. I agree.

Lord Justice Ward:

48. I also agree.