§ Mr. Wigley
asked the Secretary of State for Defence if he will make it his policy in no circumstances to give permission for any United Kingdom body, whether civil or military, to explode a nuclear bomb, either in the atmosphere or underground.
§ Mr. Mason
Our policy, as indicated in the 1975 Defence White Paper, is to maintain the effectiveness of the Polaris force and our tactical nuclear capability. In conformity with this policy, I cannot rule out the possibility that it may become necessary to conduct a further nuclear test at the United States underground testing site in Nevada. Any further test would, of course, be conducted fully in accordance with our obligations under the Partial Test Ban Treaty of 1963 and the Non-Proliferation Treaty of 1970. The yield would be well below the threshold—150 kilotons—for underground nuclear tests agreed between the United States and the Soviet Union. We have said we will act as if bound by this threshold agreement.