Bevin , Attlee 's Foreign Secretary , famously stated that " We 've got to have it and it 's got to have a bloody Union Jack on it . " The first operational British A Bomb was not detonated until October 1952 , about one year after Attlee had left office . Independent British atomic research was prompted partly by the US McMahon Act , which nullified wartime expectations of postwar US – UK collaboration in nuclear research , and prohibited Americans from communicating nuclear technology even to allied countries . British atomic bomb research was kept secret even from some members of Attlee 's own cabinet , whose loyalty or discretion seemed uncertain
British A Bomb
Operation Hurricane
Clement Attlee