DPP v Marrable, Divisional Court, 4th February 2020, Unreported.

The appellant was alleged to have driven at 72 mph where the temporary speed limit was 50 mph.

Before the magistrates’ court, the appellant contended that he had driven his company vehicle, fitted with a GPS tracker device, at 53-54 mph.

A police officer gave evidence that the speed was detected using a Home Office type-approved Trucam laser speedmeter, within calibration and operating properly.

The justices’ clerk advised the magistrates that the Trucam laser speedmeter was a Type-approved device and the defendant’s opinion of his speed was insufficient to rebut the Trucam evidence and that the GPS tracking device was not an approved device for measuring speed.

The magistrates dismissed the case against the defendant on the basis that the GPS tracker device cast a reasonable doubt as the speed of the vehicle. The prosecutor appealed by way of case stated. The DPP submitted:

The justices had been wrong to rely on the GPS evidence as it was not an approved device and no evidence had been submitted as to its reliability
If the justices had been entitled to have regard to the GPS evidence then they were wrong to prefer it to the Trucam evidence and their decision was irrational
Even on the appellant’s own evidence, he was driving in excess of the speed limit; the justices were wrong to find that he was not guilty to driving in excess of 50 mph.

Held: Appeal dismissed. It was clearly established in Cracknell v Willis [1988] RTR 1 that evidence from an approved device was not conclusive evidence. The magistrates had been properly directed that it was a matter for the court to weigh up the competing evidence and it could not be said the the justices decision was perverse or irrational. All that was required was evidence providing a reasonable doubt that the appellant had been travelling at above 50 mph.