This is a speedometer fitted to a patrol vehicle, which is used by the officer by means of a “follow check”. Speedometers must be calibrated and regularly tested in accordance with force instructions.

There are specific rules in relation to the manner of use of calibrated speedometers and if cross examination exposes that rules and ACPO guidance have not been adhered to any speed reading obtained may be excluded from evidence.

If a Court could not be satisfied beyond reasonable doubt that the speed reading was reliable or likely to be accurate you would be found not guilty and acquitted. In such a situation you would be entitled to recover your reasonable costs in preparing your defence.