asked the Secretary of State for Defence if he will list those topics on which it is not his practice to answer parliamentary Questions; and if he will list any changes in practice since 1972, indicating in each case the date on which the change was made and the relevant references in the Official Report.

The topics on which it is not the practice to provide information are as follows:Details of arms sales, operational matters, contract prices, costs of individual aircraft etc., details of research and development, the numbers of foreign forces training in the United Kingdom and accident rates for aircraft.