The Monte Bellos bomb test, 7 seconds after detonation, 3rd October 1952.
Photo: courtesy the British Nuclear Test Veterans Association.

Remnants of the atomic bomb tests

At 8am on 3rd October 1952, Britain detonated its first atom bomb aboard the HMS Plym, which was anchored offshore of Trimouille, one of the Monte Bello Islands, situated approximately 75 nautical miles north of Onslow, off the West Australian coast. The 25kilogram nuclear fission device vaporised the Plym and its surroundings in a test code named Operation Hurricane. It was the beginning of a series of 29 British nuclear tests in Australia and several South Pacific islands from 1952 to 1958, in which more than 22,000 British, 14,000 Australian and 500 New Zealand servicemen were involved.

Situated approximately 75 nautical miles north of Onslow and 20 km north of Barrow Island off the Western Australian coast, the islands were named by the French navigator Nicolas Baudin in August 1801. Baudin was evidently "discouraged by the seeming barrenness of the country, the scarcity of fresh water and the hostility of the blacks", so kept to the sea and did little else than survey the coast line and islands. Before he left, however, he named the islands after the battle of Monte Bello, where the victorious French general Jean Lannes (1769-1809), Marshall of France and later the Duke of Monte Bello, defeated the Austrians in 1800.
The flat limestone islands range in size from Hermite, the largest, at about 1,000 ha, to several small islets and rocks of less than one hectare. They are the remnants of an old coastal landform and have been separated from the mainland for more than 8000 years. No evidence has been found of Aboriginal occupation of the islands since that separation, although they probably lived there before.
The earliest known European use of the islands was in 1622, when one of Australia's first recorded shipwrecks, that of the Trial took place just west of the Monte Bellos. The survivors of the wreck spent seven days on the northern islands before setting forth for the East Indies. Only 30 could sail with the captain in the lifeboat, the rest were left to their fate on the wrecked ship. Other early navigators, Baudin in 1801, King in 1818 and Stokes in 1840 had less eventful voyages.
The development of the pearling industry along the north west coast in the late 19th Century formed the next exciting chapter in the history of the Monte Bellos. The pearlers who fished the waters and camped on the islands are probably responsible for the introduction of the cat and the black rat who in turn are accountable for the extinction of the golden bandicoot and spectacled hare wallaby.
In 1952 the British joined the exclusive nuclear club by detonating their first atomic weapon on HMS Plym, moored in Main Bay, close to Trimouille Island. Further atomic bombs were exploded on Trimouille and Alpha Islands. Many relics of the infrastructure and detonation remain today. Regular monitoring of radiation levels shows that, with the exception of ground zero sites (the exact places the bombs were detonated) radiation has dropped below levels considered dangerous to public health.
Today the waters around the Monte Bello Islands provide excellent sheltered anchorages for vessels of all sizes and are frequently visited during the winter months by numerous boats. Some islands have been zoned for recreation, while others have been reserved for the protection of nesting seabirds and turtles.

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