Grapple Y, April 28 1958

Christmas and Malden Islands were the sites of extensive atmospheric nuclear testing by the United Kingdom and United States during the late 1950s and early 1960s.

Operation Grapple was the code name for a series of British H-bomb tests. In 1957 and 58 Britain exploded nine thermonuclear bombs at Christmas and Malden Islands in the former British colony of the Line Islands, now part of the independent Republic of Kiribati.

It was the largest British military operation since World War II, involving all three branches of the UK armed services (air, land, sea) with support from the New Zealand Navy.

The first bomb was detonated eight miles above Malden Island, a uninhabited atoll, on 15 May 1957. It exploded with a force of 300 kilotons, twenty times the power of the atomic bombs that destroyed Hiroshima and Nagasaki in 1945.

As a result, Britain claimed entry into the club of nuclear super-power nations, along with the United States and the Soviet Union.

Subsequent tests – known as the Grapple X, Y and Z shots – were conducted over Christmas Island with increasingly larger yields.

An estimated 22,000 servicemen from Britain, New Zealand and Fiji served during Operation Grapple and may have been exposed to radiation from the explosions. Some 1,200 civilian and military personnel were stationed on Christmas Island.

Around 300 people lived on Christmas Island at the time. The islanders were evacuated to a British navy vessel during the tests, and then returned to the island. Another 1,600 people were living on the islands of Penrhyn, Rakahanga and Manihiki in the Northern Cook Islands 1,000 km to the south.

Britian’s nuclear weapons program ended in 1958 with the UK-US Mutual Defense Agreement. The United States conducted a further 105 nuclear weapons tests at Christmas and Johnston Islands in 1962 and 63 as part of Operation Dominic.

The British Ministry of Defense says the tests were planned and conducted with “meticulous care and the health and safety of test participants was of the utmost importance”. MOD maintains there is no evidence of excess illness or mortality amongst the veterans due to the tests or exposure to radiation, and therefore no grounds for compensation.


Operation Grapple
Operation Dominic

Christmas Island – Operation Grapple
Jane’s Oceania

Britain’s Nuclear Weapons
Nuclear Weapons Archive

UK Atmospheric Nuclear Testing Programme
UK Ministry of Defense

50 years later, the price still being paid for the atom bomb
Mail Online

Britain’s Cold War Super Weapons
Channel 4


First British Hydrogen Bomb

Thermonuclear Bombs during Operation Dominic I


2 Responses to Tests

  1. avice peters says:

    my dad was on the HMS Cook, he jumped ship in NZ in 1957 and never went back to the UK leaving another family asking questions, and starting a new family with no idea till he died in 2012.

  2. ian d powell r a f wop j o c section at grapple c i says:

    so typical of the english only people eligible are the hamilton hythe hyphem smythes

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