8 November 1957 - Grapple X
On 8 November 1957, the United Kingdom carried out its first thermonuclear test, codenamed Grapple X. It was part of the Grapple nuclear test series, which involved nine explosions over Christmas Island (Kiritimati) and Malden Island in the central Pacific Ocean between November 1957 and September 1958. The UK had conducted its first nuclear test only five years earlier in October 1952 in Australia.
…the inside of the head became intensely white, heat building inside the body to an almost unbearable temperature, appearing to radiate from inside. For seconds it was that way, then the light started to diminish along with the heat, leaving an impression of finger and knee bones like an X-ray.Christopher Noone, UK testing veteran
Grapple X was detonated over Christmas Island, at around one kilometre above ground. The two-staged design brought about a hydrogen reaction yielding 1.8 megatons. The weapons engineers had underestimated the yield by 80%. The damage caused by the explosion’s shock wave was consequently greater than expected, resulting in demolished buildings, equipment and infrastructure (see below for health effects). The next explosion, Grapple Y, yielded a massive 3 megatons – the largest nuclear test ever conducted by the UK.
The Grapple thermonuclear designs were never actually put into service. Testing these weapons mainly served the political purpose of demonstrating Britain’s thermonuclear status. After the testing series, the United States and the United Kingdom concluded the 1958 UK-US Mutual Defense Agreement and cooperated closely in their nuclear weapons programmes.
Christmas Island served as the main base, with several thousand servicemen stationed there during the operation, including over 500 naval personnel from New Zealand. As all Grapple bombs were detonated in the air, dropped either from an aircraft or suspended from a set of barrage balloons, they produced high amounts of radioactive fallout.
Before we went off duty, we were ordered to kill the birds which had been injured by the explosion. Some were still flying around but they were blind as their eyes had been burnt out.Kenneth McGinley, UK testing veteran
The debate about the health effects of British nuclear testing in the Pacific has resulted in a long legal battle which continues up until today. Veterans from the UK and New Zealand have questioned the adequacy of radiological safety standards during the Grapple operation, claiming that they were used as “guinea pigs”. During the test trials, servicemen were free to move around the island, consuming local water and fruits, bathing in the lagoons and breathing in dust, all of which could have been contaminated.
In 2005, a study by Massey University in New Zealand concluded that sailors who observed the tests from nearby ships had experienced genetic damage. Following the publication of the study, a class action lawsuit was filed against the British Ministry of Defence by various veterans' organizations. The British Ministry of Defence maintains that only a few people were exposed to dangerous radiation and that reliable conclusions are difficult to draw from the studies.
The UK conducted its last of 45 nuclear tests on 26 November 1991. It signed the Comprehensive Nuclear-Test-Ban Treaty (CTBT) on 24 September 1996, the day it opened for signature, subsequently ratifying it on 6 April 1998.
- Nuclear Weapon Archive: British Nuclear Testing
- Britain’s nuclear test veterans fight for justice (Britain’s Pacific Nukes)
- New Zealand Nuclear Test Veterans’ Study – A Cytogenetic Analysis (Massey University, PDF)
- UK Atmospheric Nuclear Testing Program (British Ministry of Defense)
- UK House of Commons Debate on 22 October 2008
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