HC Deb 23 May 1957 vol 570 c1394
46. Dr. Stross

asked the Prime Minister whether the casing of the hydrogen bomb which was exploded on 15th May in the Pacific Ocean was free from uranium or plutonium.

The Prime Minister

As I said in my statement in reply to Questions on Tuesday, for reasons of national security I am unable to pass on to the House any detailed information about the precise type and design of the weapon exploded.