Vx Nerve Gas Mr. Shersby asked the Secretary of State for Defence what classification was given by the Patent Office to patent application No. 24022/62 filed by the Secretary of State for Defence on 22nd June 1962 in respect of VX nerve gas; whether any change in classification has been made since the original application; and, if so, whether the interests of national security were considered in relation to such a change. Mr. William Rodgers Patent Application No. 24022/62 does not relate to VX nerve gas but to improvements in the process of manufacture of a class of compounds of which VX is a member. The application was classified by the Patent Office following notification by the War Office that the invention to which the application related was secret. Classification was removed by the Patent Office following notification by the Ministry of Defence in 1973 that publication of the application need no longer be prohibited. The interests of national security were considered by the Ministry of Defence in authorising this change of classification.