Lord Penney, creator of the British atomic bomb in the 1950s and the only Briton to observe the atomic bombing of Nagasaki, Japan, in 1945, has died, his family announced Wednesday.
Penney, who was 81, died Sunday at his home in the village of East Hendred, west of London. No cause of death was given.
Born William Penney and knighted in 1952--the year Great Britain exploded its first atomic bomb--Penney studied mathematics at London University's Imperial College, the University of Wisconsin and Cambridge University. In 1936, he became assistant professor of mathematics at Imperial College, where he turned to nuclear physics.
Soon after the start of World War II in 1939, he began working for the government on weapons research.
In 1944, he became principal scientific officer of the British team involved in the atomic bomb development project at Los Alamos, N.M.
Penney advised on the construction of the world's first atomic bomb, which was exploded near Alamogordo, N.M., on July 16, 1945. He also helped assemble the nuclear bomb that was dropped on Hiroshima, Japan, on Aug. 6, 1945.
He later admitted to qualms of conscience about his part in the development of atomic weapons. But he said he was convinced Britain had to have them and argued that the doctrine of mutually assured destruction would make major wars impossible.
On Oct. 3, 1952, he directed from an aircraft carrier the test explosion of Britain's first atomic bomb in the Monte Bello Islands off the northwest coast of western Australia.
The British weapon reduced the critical mass of uranium needed for the explosion, leading to a smaller but equally powerful bomb.
Penney was director of the government's Atomic Weapons Research Establishment from 1953 to 1959. In 1954, he also became responsible for weapons research at the United Kingdom Atomic Energy Authority.
In 1959, he became the authority's member for scientific research, concentrating on long-term research into peaceful uses of nuclear energy, including projects to develop cheap electricity.
In 1985, he was questioned by the Australian Royal Commission investigating safety standards of Britain's 1950s test program at Monte Bello and Maralinga. He acknowledged that "in hindsight" at least one of the 12 devices in those tests was exploded in unsafe conditions.