§ 57. Mr. A. Hendersonasked the Secretary of State for Foreign Affairs whether it is the policy of Her Majesty's Government to extend the 1963 Test Ban Treaty to those categories of underground nuclear explosions which can now be detected and verified by national means.
§ Mr. R. A. ButlerNo. Our objective must be a comprehensive ban. I am advised that it would be very difficult to define a threshold above which scientists would be prepared to assert that all underground tests could be conclusively identified, unless it were so high as to permit the great majority of tests to continue.