page_title: Nuclear weapons and the United Kingdom
section_title: Nuclear tests
hierarchical_section_title: Nuclear weapons and the United Kingdom / Nuclear tests
caption_attribution_description: English: Site of first atomic test on mainland Australia, known as Totem One. Photo taken by Gazjo on 1st January 2006
context_page_description: In 1952 the United Kingdom became the third country to develop and test nuclear weapons, and is one of the five nuclear-weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons.
  The UK initiated a nuclear weapons programme, codenamed Tube Alloys, during the Second World War. At the Quebec Conference in August 1943, it was merged with the American Manhattan Project. The British contribution to the Manhattan Project saw British scientists participate in most of its work. The British government considered nuclear weapons to be a joint discovery, but the American Atomic Energy Act of 1946 restricted other countries, including the UK, from access to information about nuclear weapons. Fearing the loss of Britain's great power status, the UK resumed its own project, now codenamed High Explosive Research. On 3 October 1952, it detonated an atomic bomb in the Monte Bello Islands of Western Australia in Operation Hurricane. Eleven more British nuclear weapons tests in Australia were carried out over the following decade, including seven British nuclear tests at Maralinga in 1956 and 1957.
context_section_description: The UK's first nuclear test, Operation Hurricane, was in the Montebello Islands of Western Australia. It was followed by the first nuclear tests on the Australian mainland, which were conducted at Emu Field in the Great Victoria Desert in South Australia as part of Operation Totem on 14 and 26 October 1953. Two further tests were held on the Montebello Islands as part of Operation Mosaic on 6 May and 19 June 1956. In the 1980s there emerged a claim that the second Mosaic test was of a significantly higher explosive yield than suggested by available figures—98 kilotonnes of TNT (410 TJ) as compared to the official figure of 60 kilotonnes of TNT (250 TJ)—but this claim does not stand up to scrutiny.
  The British government formally requested a permanent test facility on 30 October 1953. Due to concerns about nuclear fallout from the previous tests at Emu Field and the site's inadequate infrastructure and water supply, the recently surveyed site at Maralinga in South Australia was selected for this purpose. The new site was announced in May 1955. It was developed as a joint, co-funded facility between the British and Australian governments. Seven British nuclear tests at Maralinga were conducted between 27 September 1956 and 9 October 1957.
  In addition to the major tests involving explosions, many subcritical minor trials were also carried out between June 1955 and April 1963. While the major tests had been carried out with some publicity, the minor tests were carried out in absolute secrecy. The "Kitten" tests tested bomb components, while "Tims" and "Rats" were early subcritical hydronuclear tests.  The "Vixen" tests involved safety testing of nuclear weapons—assuring that the core would not accidentally undergo criticality in the event of a fire or crash. These minor tests left a legacy of radioactive contamination at Maralinga.
  The Australian government prohibited hydrogen bomb tests in Australia, so Britain had to look for another test site for its hydrogen bombs. The first British hydrogen bombs were tested during Operation Grapple at Malden Island and Christmas Island in the Pacific Ocean. Nine tests were conducted there in 1957, 1958 and 1959, ultimately demonstrating that the UK had developed expertise in thermonuclear weapons.
  Beginning in December 1962, the UK conducted 24 tests at the Nevada Test Site in the United States. The final test was the Julin Bristol shot which took place on 26 November 1991. British nuclear testing was abruptly halted by President George H. W. Bush in October 1992.  Because Britain did not test as often as the United States for financial and political reasons, and did not have the Americans' state-of-the-art computer facilities, British weapons design depended more on theoretical understanding, with potential for both greater advances and greater risks between tests.
  The United Kingdom, along with the United States and the Soviet Union, signed the Partial Test Ban Treaty, which restricted it to underground nuclear tests by outlawing testing in the atmosphere, underwater, or in outer space, on 5 August 1963. The UK signed the Comprehensive Test Ban Treaty, ending all nuclear testing, on 24 September 1996, and ratified it on 6 April 1998, having passed the necessary legislation on 18 March 1998 as the Nuclear Explosions (Prohibition and Inspections) Act 1998. Subcritical nuclear tests continued to occur, most notably the Etna test in February 2002, and the Krakatau test in February 2006.
  Altogether Forty-five nuclear tests were carried out by the United Kingdom between 3 October 1952 to 26 November 1991 at the Montebello Islands, Emu Field and Maralinga in Australia, on Christmas and Malden Islands in Kiribati, and at the Nevada Test Site in the United States. The 45 tests included 21 tests carried out in the atmosphere.
caption: Site of Totem 1, the first nuclear test on the Australian mainland
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