§ Mr. Livingstone
To ask the Secretary of State for the Home Department what tests and studies have been carried out since 1965 by police departments on CS gas or CS gas foam; what was the purpose of these tests; where the tests were carried out and by whom; what was the nature of these tests; when the tests were carried out; what is the Home Office's policy on the use of CS gas or CS gas foam; and what assistance the police received from the Chemical and Biological Defence Establishment, Porton Down, during these tests. 
§ Mr. Maclean
Individual police forces have not, so far as I am aware, carried out their own scientific research into CS. They do, however, have access to the results of research and to expert advice. The report of the Home Office inquiry into the medical toxicological aspects of CS, published in two parts in 1969 and 1971—Command Papers 4173 and 4775 respectively—included a thorough review of the substantial research which had been carried out into CS at that time. This has subsequently been complemented by further research which has been reported upon in the published literature. This is kept under expert review by the Home Office police scientific development branch, which in turn provides chief officers of police with advice on the operational suitability of particular products.
The police scientific development branch has, in consultation with the Department of Health and the Chemical and Biological Defence Establishment, recently reviewed the latest available information in relation to proposals for the carriage of CS by police officers for self-defence. The police have for some years had access to CS for use against armed besieged criminals or as a last resort in public disorder.
It is for chief officers of police to choose which CS devices to deploy, or the medium in which the irritant is dispensed, in any given circumstances. It is planned to use hand-held canisters which spray CS in a liquid solution for police self-defence trials.