asked the Secretary of State for the Home Department particulars of the reports received by his Department on the experiments that have been made in the method of testing speeds for motorists by the use of the invisible ray process; and whether it is proposed to recommend the use of this system for replacing the methods at present adopted for enforcing the speed limit?

This method of detecting infringements of the speed limits was tried by the Cheshire police in 1936. The experiment revealed certain disadvantages in the use of the invisible ray device for this purpose, and it was discontinued after a few months. So far as my right hon. Friend is aware the experiment has not been repeated in this country.

Were any disadvantages revealed?

One of the disadvantages was that the ray might be deflected by a motor car or even by a leaf or by a bird.

Can the hon. Gentleman say whether these disadvantages are greater than those inflicted on the private motorist by being placed completely at the mercy of two police constables who might be desirous of having a case?

Is my hon. Friend aware that the present system of dealing with motor cars is most unreliable and unsatisfactory and has been abandoned in South Africa?