To ask the Secretary of State for Defence (1) if the new Trident missile submarine programme is being complemented by improvements to the capabilities of existing submarine command, control and communications systems;(2) if the new Trident missile submarine programme is being complemented by efforts to reduce the vulnerability of elements of the existing submarine command, control and communications system;(3) if the new Trident submarine programme is being complemented by any new submarine command, control and communications system.

Communications system for Trident submarines will be fully effective on its introduction into service in the mid 1990s. I am unable to comment further for reasons of security.