The Road Vehicles (Construction and Use) Regulations 1986

6.  A motor cycle shall regarded as complying with paragraph (c) of the definition of “moped” in paragraph 5 if it cannot exceed 35 mph when tested under the following conditions—

(a) the surface on which it is tested shall be dry asphalt or concrete;

(b) the rider shall be a person not exceeding 75 kg in weight;

(c) no passenger or load shall be carried;

(d) the test route shall be so located that acceleration to, and deceleration from, maximum speed can take place elsewhere than on the test route itself;

(e) the test route shall not have a gradient exceeding 5%;

(f) the motor cycle shall be ridden in opposite directions along the test route and the speed recorded for the purpose of the test shall (in order to minimise the effect of wind resistance and gradient) be the average of speeds shown for each direction;

(g) when being driven along the test route, the motor cycle shall be driven in such manner and in such gear as to achieve the maximum speed of which it is capable; and

(h) if the motor cycle is fitted with a device which can, without the use of specialist tools or equipment, be readily modified or removed so as to increase its maximum speed, the test shall be carried out with the device in the modified condition or, as the case may be, without the device.