On 11 January 1956, British newspapers reported on an RAF force preparing to support the country’s next atomic trials at the Monte Bello Islands, off the coast of Western Australia. The reports named the force’s commander as Group Captain S. W. B. Menaul and described the arrival of his advance party at a Royal Australian Air Force base near Perth, ahead of the Canberra bomber operations the task force would fly from there later in the year.
The force itself had been formed months earlier. What British newspapers reported on 11 January was the latest stage in preparations that had been under way since the previous autumn, as Britain moved toward a second round of atomic tests at the remote island site it had used in 1952.
A task force already months in the making
No. 308/5 Air Task Force, later redesignated 308.5 Task Group, formed at RAF Weston Zoyland in Somerset on 15 October 1955 under the command of Group Captain S. W. B. Menaul. Its purpose was to provide the RAF element of Operation Mosaic, the codename for Britain’s second series of nuclear weapons trials at Monte Bello. The task group comprised 514 personnel, 107 officers and 407 other ranks, drawn together over the following weeks to prepare aircraft, equipment and aircrew for the deployment to Australia. Menaul spent the closing months of 1955 assembling and training the force he would lead to the other side of the world.
The RAF reaches Australia
The advance party of Menaul’s task force reached RAAF Pearce, near Perth in Western Australia, on 10 January 1956. Pearce would become the RAF’s main base for the operation as the rest of the task group arrived over the following months, with elements also operating from Onslow and RAAF Darwin. British newspapers reported the arrival of the advance party at Pearce, and the wider preparations it represented, the following day.
Operation Mosaic and the 1956 tests
Britain’s pursuit of an independent nuclear deterrent had begun in secret in the late 1940s and produced its first atomic test at Monte Bello in October 1952. Operation Hurricane made Britain the world’s third country to test a nuclear weapon, after the United States and the Soviet Union. By the mid-1950s, British scientists were working towards more powerful weapon designs, and Operation Mosaic became the second series of British nuclear tests at Monte Bello.
The first Mosaic device, G1, was detonated on Trimouille Island on 16 May 1956. The second, G2, followed on Alpha Island on 19 June. Published estimates of G2’s yield range from about 56 to 98 kilotonnes. It was the largest nuclear detonation conducted in Australia.
The RAF role in Operation Mosaic
Menaul’s task group supplied the aircraft and aircrew that carried out the RAF’s part of Operation Mosaic. English Electric Canberras operating from RAAF Pearce undertook cloud sampling and tracking after the detonations, with Menaul flying one of the Canberras that sampled cloud from G1 in May. Vickers Varsities also took part in cloud tracking and aerial radiological survey work, while RAF helicopters supported survey operations. Operational flying for Mosaic was an RAF responsibility, making air operations an important part of both conducting the trials and collecting scientific information afterwards.
On 11 January 1956, British readers learned that a task force three months in existence had begun reaching Australia, its advance party now at Pearce ahead of tests still four months away. The RAF’s role in Britain’s second round of atomic trials at Monte Bello had shifted from formation in Britain to deployment in Australia, where the tests would take place.