Clarke v Crown Prosecution Service

English law does not require a speed-measuring device to be checked for accuracy before its reading can corroborate a police officer’s opinion of excess speed. The absence of testing may affect the weight of the evidence in a particular case, but it does not create an automatic admissibility or conviction bar. Operational manuals and professional guidance may recommend testing as good practice without imposing legal requirements. A court may rely on the device where the officer conducted sensible checks, the device indicated that it was functioning properly, and there is no evidence suggesting unreliability. Scottish authority does not justify replacing the established domestic approach.

The appellant appealed by way of case stated against his conviction by Staines Magistrates’ Court for exceeding a 50 mph speed limit. A police community support officer formed an opinion that he was speeding and obtained a reading of 68 mph from an Ultralyte 20/20 device.

The appellant argued that the device’s accuracy had not been sufficiently verified because the officer had relied on another officer’s measurement of a fixed test distance. He relied on Scottish authority, professional guidance and The Queen on the Application of Seroka v Redhill Magistrates’ Court. The central issues were whether the device could be relied upon, whether the hearsay evidence was admissible, and whether the magistrates were right not to follow Cox v Procurator Fiscal, Aberdeen.

1. Appeal dismissed. The court answered questions 2 and 3 in the affirmative. It was unnecessary to answer question 1 concerning hearsay because that issue was irrelevant to the result.
2. Section 89(2) of the Road Traffic Regulation Act 1984 prevents conviction solely on one witness’s opinion that the defendant exceeded the limit. It does not require proof that a corroborating speed-measuring device has been tested for accuracy.
3. The established domestic authorities, including Nicholas v Penny, Swain v Gillett and Kelly Communications v DPP, supported an approach under which strict proof of testing is unnecessary unless particular facts cause the court to regard the evidence as having insufficient or no weight without confirmation that the device was functioning correctly.
4. The operator’s manual and Association of Chief Police Officers guidance recommended checks and recording procedures. They represented cautious best practice rather than absolute legal requirements. There was no evidence that devices of this kind were prone to unreliable results, and the officer had conducted several checks, including a site distance check before and after the reading. The device gave no error indication.
5. Cox v Procurator Fiscal, Aberdeen concerned a different device and did not require a rigid approach to testing. Scottish and English law had diverged in significant areas, and there was no evidential basis for replacing the established English approach.
6. The Queen on the Application of Seroka v Redhill Magistrates’ Court did not establish the suggested requirement. That case principally concerned the admissibility of Gatsometer records and did not decide the issue arising here.
7. The magistrates’ approach was essentially faultless. The conviction was upheld, and the appellant was ordered to pay the respondent’s costs of £645.

High Court (Administrative Court): The appeal by way of case stated was dismissed. The magistrates’ conviction was upheld.