Appellant: L Prais; Michael Lyon Solicitors, Glasgow

Respondent: AF Stewart QC, AD; Crown Agent

14 June 2012

[1] The appellant was convicted, at the Justice of the Peace Court in Annan, of speeding on the A701 Dumfries to Edinburgh Road, near Heathhall. The allegation was that he was driving at 53mph in a 30mph area. Police officers gave evidence on the use of a Kustom Cordless Falcon Speed Detection device. The device was tested, according to the police, prior to use and it appeared to be functioning properly. It was also tested after use. The tests which were carried out involved four different mechanisms. First, there was an on-off test during which all the LEDs were displayed. Secondly, there was an internal test involving a test button, which produced the correct speed reading. Thirdly, and most important for the purposes of the appeal, there was a test using a tuning fork. The fork was unique to the device and, when used, the frequency produced resulted in the correct speed reading being displayed. Finally, the machine was returned annually to the manufacturer for remote calibration.

[2] The police observed the appellant's car approaching at a speed that they assessed as in excess of 30mph. The device was trained upon the car. It recorded a speed of 53mph, which broadly accorded with the police opinion.

[3] It was contended before the Justices of the Peace, and before this court, that the appellant's "no case to answer" submission ought to have been sustained. This contention was based on the proposition that the respondent had failed to lead sufficient evidence of the accuracy of the device. In particular, where proof of a precise speed was necessary and that proof was offered by means of a device, the respondent required to lead evidence of the accuracy of that device (McLean v McLeod 2002 SCCR 127, Lord Coulsfield at para [6]). It was submitted that the respondent had failed to lead sufficient evidence to demonstrate that accuracy. The particular test under attack was the one which involved an external check using the tuning fork. On an analogy with the circumstances in Hogg v McNeill 2001 SCCR 134, it was submitted that the absence of proof of the accuracy of the tuning fork's frequency was akin to the failure in Hogg to demonstrate the accuracy of the measured half mile. There was no evidence of the frequency of the tuning fork and it was possible that the fork had, in some way, become degraded to produce a different frequency from that produced when it was originally manufactured and tested. Without an external test on the day of the alleged offence, it was not possible to say if the fork had produced an accurate frequency when used and therefore whether the device had given an accurate determination of speed at the material time. Put shortly, it was said that the respondent needed to lead direct evidence of the accuracy of the frequency of the tuning fork. Under reference to Cox v McGowan 2011 SCCR 265, and to Purves v Clarke 2001 SCCR 138, it was stressed that the tuning fork was not akin to the steel tape used for proof of distance. The clear and concise submission made to the court can be summed up in the final contention that this was not an attempt to extend the principles of Hogg and Cox, but an effort to apply these principles appropriately to a different, more modern, speed recording device.

[4] The court proceeds, for present purposes, on the basis that it is necessary for the respondent to lead evidence that a particular device is working accurately at the material time (McLean v McLeod 2002 SCCR 127). However, this case involved the police giving evidence that four tests were carried out to ensure that accuracy. Focussing in particular on the tuning fork, the court is of the view that the Justices were entitled to hold, from the evidence which was adduced before them, that the device was working accurately, although they need not have done so if there had been any apparent deficiency in the testing methodology or results. The tuning fork is a physical object which is used to check the accuracy of the machine. It is manufactured to provide an immutable frequency when employed. There is no need to go back, in every case, to check that each piece of checking equipment has itself been checked and found to be accurate. The Justices of the Peace were entitled to hold from the evidence given, including that of the tuning fork test, that the device was working properly. Therefore, the court is bound to answer both questions in the stated case in the affirmative and to refuse the appeal.