Titterton’s experience recommended him to the British and Australian governments when, from 1952 to 1963, British nuclear weapons were tested in Australia. He was a foundation member and later chairman of the Atomic Weapons Tests Safety Committee that oversaw the safety of Australian people, property and countryside. Many people were troubled by his persistent assurances that nuclear energy was safe, that nuclear weapons were desirable and that the fission yield from the 1960 ‘Vixen B’ trials was zero.

In 1950 Titterton accepted Oliphant’s invitation to become foundation professor of nuclear physics, Research School of Physical Sciences, Australian National University, Canberra, initially to study atomic nuclei with accelerated particles and later to participate in particle physics, using Oliphant’s planned ‘big machine’. Titterton’s first task was to house and test the first accelerators—a Cockroft-Walton and an electron synchrotron. Arranged through the respective governments, the latter acquisition enabled him to meet Prime Minister (Sir) Robert Menzies, with whom he formed a close relationship.

appointed a consultant to the Atomic Weapons Research Establishment at Aldermaston, he witnessed the development of a British nuclear weapon.

In 1943 he joined the Manhattan Project at Los Alamos, United States of America. Here he helped to design the explosive lens system that shaped the initial shock wave to the spherical (‘fat man’) bomb, and the sequential timing system necessary for its detonation. He triggered the first bomb test (‘Trinity’) on 16 July 1945. Subsequently, a cylindrical (‘little boy’) bomb was exploded over Hiroshima and a ‘fat man’ over Nagasaki.

in 1947 Titterton returned to Britain. At the Atomic Energy Research Establishment, Harwell, he was in charge of a nuclear physics research group that conducted pioneering studies of ternary fission—the decay of highly excited light nuclei and multi-particle disintegrations produced by fast neutrons

He next collaborated with Otto Frisch at Birmingham and Liverpool to develop a British nuclear weapon