Operation Grapple with the American Manhattan Project in August 1943. Many of Britain's top scientists participated in the British contribution to the Manhattan Project. After the war, fearing that Britain would lose its great power status, the British government resumed the atomic bomb development effort, now codenamed High Explosive Research. The successful test of an atomic bomb in Operation Hurricane in October 1952 represented an extraordinary scientific and technological achievement, but Britain was still several years behind the United States in nuclear weapons technology. In July 1954, the Cabinet decided to develop the hydrogen bomb. The United Kingdom Atomic Energy Authority Atomic
Atomic demolition munition and all were removed from stockpile by 1966. A weapons effect test of the TADM was made in the 1962 Johnny Boy ("Johnnie Boy") shot of the Dominic II series (which is more accurately referred to as Operation Sunbeam), the yield of Johnny Boy/Johnnie Boy was about .5 kt. A preceding ADM test which resulted in a comparable yield, was test shot "Danny Boy" of Operation Nougat, also producing a yield of about 0.5 kiloton. The "Special Atomic Demolition Munition (SADM)" was a family of man-portable nuclear weapons fielded by the US military in the 1960s, but never used in