Air Defences 40. Mr. Litherland asked the Secretary of State for Defence if he plans to strengthen air defences between now and 1991. Mr. Stanley The defence of RAF establishments against possible air attack will benefit from the major programme of improvements in both the quantity and quality of our air defences which is now under way including the programmes for the Tornado air defence variant, the Boeing E-3A and improved UKADGE. In addition, specific measures are being taken to ensure survivability and the continuance of air operations, for example by hardening aircraft shelters and other key facilities and by extending our airfield damage repair capabilities.