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Operation Grapple

Britain’s Development of the Nuclear Bomb

By Russ Glackin – original article published in The White Ensign Issue 05, 2008.

When the USA dropped atomic bombs on Hiroshima  and Nagasaki, Japan in August 1945 to end World War Two in the Pacific, they made the possession of nuclear power a major requisite for Great Power status in the post-war world. The British, no less than the Russians and French scrambled to close what they saw as an alarming nuclear gap that had been opened by the Americans and so began a nuclear arms race that was the very essence of the Cold War. There in lay the seeds of Britain’s Operation Grapple in the South Pacific.

Allies at Odds

Britain’s scientists had long conceived of the concept of nuclear power and were committed to the development of nuclear weapons but it was not until two nuclear scientists at the University of Birmingham published a paper in 1940, theorising on the source of the fast chain reaction necessary for an atomic bomb, that the concept became feasible. The Maud Committee was immediately set up to explore the possibility of the feasibility becoming a reality.

When the Americans read the first Maud Report they were impressed at how technically advanced the British were, and pressed Roosevelt to set up the Manhattan Project and propose a collaboration with the British. Britain’s chilly response was ironically at odds with what later transpired, but they were concerned at the ability of the Americans to keep secrets. They were uneasy about America’s neutral position in the war at that point and they were understandably reluctant to surrender their nuclear advantage which would be vital in the post-war world.

Britain needed America’s help to win the war. Churchill accompanied by his daughter, travelled to America to request Franklin Roosevelt to come into the war.

Pearl Harbour Bombing Galvanises America

The American and British roles were dramatically reversed by the Japanese Bombing of Pearl Harbour in December 1941. Committing America to the war and the atomic bomb, Roosevelt poured vast quantities of money, materials and manpower into the Manhattan Project against which a war-torn Britain could not compete.

Churchill’s formidable diplomatic skills were needed to persuade Roosevelt to give British scientists the opportunity to join the Manhattan team at Los Alamos, in a desperate bid to build the bomb before the end of the war. Though the British scientists on the Project were ‘compartmentalised’ by the Americans and prevented from getting an overall view of the work on the bomb, their contribution to the development of the Hiroshima bomb was vital, and they returned home with a working manual on how to duplicate the American atomic bomb.

Pearl Harbour - USN/Public Domain

Successful testing of Britain’s megaton range nuclear weapons during Operation Grapple required the cooperation of the three military services and civilian scientists. These four main arms are symbolised in the 4-pointed grapnel carried by a cormorant. The cormorant is a symbol frequently used for inter-service cooperation.

This booklet was created for the information of the men who worked on Operation Grapple. The introduction by Task Force Commander Air Vice-Marshall W.E. Oulton suggests it would “serve as a pleasant souvenir of what must surely be one of the most interesting periods of your lives.”

Souvenir Booklet for men serving in Operation Grapple, published by the British Government c 1956. 2007.7.23

Monte Bello Island Test Site in Australia

The priority was to explode a nuclear device as soon as possible. Britain needed an isolated test site large enough to conduct twelve tests, with no human habitation within 100 miles downwind of a detonation, and where prevailing winds would blow contamination out to sea but not into shipping lanes.

In early 1952, Australian’s pro-British Prime Minister, Robert Menzies, keen for Australia to start a nuclear energy programme of their own, readily agreed to allow Britain’s first atomic bomb test to be conducted on the uninhabited Monte Bello Islands off Australia’s north-west coast. He assured Australians that ‘the test… will be conducted in conditions which will ensure that there will be no danger whatever from radioactivity to the health of people or animals in the Commonwealth’, whilst neglecting to mention that it was probably the first test in an ongoing programme and would leave the islands uninhabitable for years.

Britain exploded its first A-bomb at Monte Bello at 9.15am on 3 October 1952, amidst great secrecy and urgency. It went faultlessly.

Britain had joined an exclusive club, but had singularly failed to impress its members for only a month after Monte Bello, the USA exploded her first H-bomb followed by the Soviets in August 1953. It was, however, the beginning of Britain’s programme of atmospheric nuclear tests that was to end with Operation Grapple Z on 23 September 1958.

New Test Sites Needed 

The original test-site on the Monte Bello Islands proved to be unsuitable. A further two new test sites were developed at Maralinga and Christmas Island. An aboriginal place name, Maralinga portentously translates as ‘field of thunder’.

The test site at Maralinga was completed in early 1956 at a cost of five million pounds. At the same time construction had already begun at Christmas Island – now known as Kiritimati.

Developing a British H-Bomb

Britain decided to manufacture its H-bomb in June 1954 as the Americans and Russians had already developed and tested their H-bombs. They got a “bigger bang for their buck” as the H-bomb was cheaper to manufacture than the A-bomb.

The original Test Agreement with the Australians had specifically excluded hydrogen weapon testing on the Australian mainland so the hunt was on for another testing ground.

The requirements for the new site were British ownership in the largest area of the sea with the least number of adjacent land masses and the least number of people.

The finger fell upon Christmas Island, the Pacific’s largest atoll, a 1000 miles south of Hawaii and 1500 miles north of Fiji and adjacent to Malden Island.

The British H-bomb tests on Christmas Island, were code-named Operation Grapple. The 4-pointed iron grapple symbolising inter-service cooperation on the project – Army, Navy, Airforce and AWRE, the Atomic Weapons Research Establishment.

The period 1957 -1958 saw direct New Zealand Navy involvement in nuclear testing, when RNZN sailors were deployed at the request of the British to witness nuclear testing off the coasts of Christmas and Malden Islands in the Pacific.

These tests were the final block carried out by Britain in Australia and the Pacific. Five hundred and fifty one men and two frigates; HMNZS Rotoiti and Pukaki comprised New Zealand’s contribution. Their official duties were to witness the explosions and collect weather data, although some New Zealand sailors also monitored the test area for Russian and American spy-submarines.

The first bomb was dropped from a Valiant bomber at 13000 feet on 15 May 1957. Many who witnessed the blast were astonished and terrified by its power. William Oates, a storeman on the island recalled, “Probably the thing that scared me the most was not the ball of flame in the sky, not the searing heat but the blast and shock wave which followed later… I saw grown men at their wits end trying to run away from the blast.”

Operation Grapple ended in September 1958, and just in the nick of time as Britain joined the USA and the USSR in the next month in a moratorium on nuclear testing. Britain never tested in the open again, but Christmas Island was back in business by 1962 as a test site for the Americans.

The moratorium collapsed with the Soviets began testing again in 1961, and Britain lent their test site to the USA for a series of 25 tests called Operation Dominic which they used to refine their Polaris missiles. When Britain Purchased the Polaris missiles from the Americans, they effectively ended their own independent nuclear deterrent by becoming reliant on the USA for supply. Thereby denying the original objective of their nuclear programme they’d had since the end of World War Two.

-Russ Glackin first published in Issue 05 White Ensign


  • Blakeway Denys, Sue Lloyd-Roberts – Fields of Thunder: Testing Britain’s Bomb: London: Unwin 1985.
  • Crawford, John, The involvement of Royal New Zealand Navy in the British Nuclear Testing programme of 1957 and 1958, Wellington: Headquarters New Zealand Defence Force, 1989. Ministry of Defence, Operation GRAPPLE.
  • 1956-1957, London: HMSO, 1958.
  • Wright, Gerry. We were There: Operation Grapple. New Plymouth: Zenith Publishing, n.d.

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