Operation Hurricane was the first test of a British atomic device. A plutonium implosion device was detonated on 3 October 1952 in Main Bay, Trimouille Island, in the Montebello Islands in Western Australia. With the success of Operation Hurricane, the United Kingdom became the third nuclear power, after the United States and the Soviet Union.
During the Second World War, Britain commenced a nuclear weapons project, code-named Tube Alloys, but the 1943 Quebec Agreement merged it with the American Manhattan Project. Several key British scientists worked on the Manhattan Project, but after the war the American government ended cooperation on nuclear weapons. In January 1947, a cabinet sub-committee decided to resume British efforts to build nuclear weapons, in response to an apprehension of American isolationism and fears of Britain losing its great power status. The project was called High Explosive Research, and was directed by Lord Portal, with William Penney in charge of bomb design.
Wikipedia https://en.wikipedia.org/wiki/Operation_Hurricane
Address Australia
Coordinates -20°23'49.2" N 115°33'30.24" E