The devices challenged were the LTI 20.20 TS/M Speedscope; the LTI 20.20 Ultralyte 100. Both of those are mobile speed cameras. The operator points the device at the rear of the vehicle which he thinks is speeding and pulls the trigger. This activates a laser beam enabling measurement of the vehicle's speed. Also challenged was the Gatsometer 24 - a speed camera which operates on radar principles.
Parliament "prescribed" the use
of radar measurement in the Road Traffic Offenders (Prescribed Devices) Order 1992 . A similar Order of 1993 prescribes (a) a device designed or adapted for recording a measurement of the speed of motor vehicles activated by means of sensors or cables on or near the surface of the highway; and (b) a device designed or adapted for recording a measurement of the speed of motor vehicles activated by means of a light beam or beams.
Having "prescribed" the devices in this way, it is then a matter for the Secretary of State to "approve" the use of particular devices such as those mentioned earlier. A list of approved devices as at March 2007 may be seen via the Home Office website - here.
By the Road Traffic Offenders Act 1988 s.20 - evidence of speed measured using "prescribed" devices is admissible. However, under section 20(4), the prescribed device must be of a type approved by the Secretary of State and it must be used in accordance with any conditions subject to which the approval was given. Section 20(9) defines “prescribed device” as a device of a description specified in an order made by the Secretary of State.
The drivers argued that the generic descriptions used in the 1992 and the 1993 Orders were too vague and broad to meet the requirements of section 20 and that the Secretary of State should have approved the device before placing the statutory instrument before Parliament.
The High Court considered some Scottish case law - which is of "persuasive authority" - and concluded that the plain effect of section 20 (4) is that the requirement for the type of the device to be approved is additional to the requirement that the description of the device is specified in the relevant statutory instrument. The statutory instrument did not need to specify the particular device.
This interpretation of the law makes good sense since it permits new devices to be approved by the Secretary of State without necessarily having to amend the legislation. In this way, new technology can be more readily brought into use.