At the time, Britain was in the middle of the Blitz, which lasted from September 1940 until May 1941, so it was not a safe place to develop the bomb. They needed to find somewhere else.
The Maud Report on the atomic bomb was sent up the chain of command to the highest levels of the British Government. Several months later a new entity was created: the Directorate of Tube Alloys, housed within the Department of Scientific and Industrial Research. Tube Alloys was Britain’s new A-bomb establishment, the forerunner to the organisation that later tested bombs in Australia. The name was marvellously enigmatic – indeed, as Gowing described it, ‘meaningless and unintelligible’ – and most likely to be associated in the casual observer’s mind with aeroplane or tank parts. Such a simple strategy was remarkably successful and provided excellent cover.
While the Maud Committee stage-managed the realisation of the dangerous Frisch–Peierls idea, the US was working on its own top-secret physics separately. The Americans had not yet been party to the Frisch–Peierls Memorandum; if they had, their work might by then have been further advanced than the British. But at this point, Britain was well in front. For the idea of the bomb to be made real, though, it would have to shift across the Atlantic.
Some insiders in Britain wanted the bomb-building infrastructure to be established in Canada, a close and trusted member of the Commonwealth and the main supplier at that stage of uranium oxide, but in the end the better equipped US had to be the choice. After a slow start, American atomic bomb research was accelerating. A summary of the activities of the Maud Committee was transmitted to the US in July 1941, although the Maud Report itself did not arrive until October. News about the Maud scientists and the contents of the Frisch–Peierls Memorandum (so far unseen in the US) had an instant effect. Mark Oliphant was among the insiders who took this knowledge to America in 1941, speaking to US military officials and fellow physicists. He found an attentive reception. Such visits led to a chain reaction of information, and the physics world in America lit up. The American physicists, now in possession of the work by the Maud scientists as well as their own escalating research, understood immediately what could be unleashed.
In December 1941, just after the Japanese attack on Pearl Harbor brought the US into the war, the US Government established the Office of Scientific Research and Development to pursue atomic weapons science. This organisation began collaborating with the new Directorate of Tube Alloys, intensifying the information flow across the Atlantic for a short while. In the US, Glenn Seaborg pioneered research on the chemistry of plutonium at Berkeley in California that proved essential to bomb development. In the Metallurgical Laboratories in Chicago sufficient quantities of plutonium were created for the first time. The Americans, in remarkably quick time, did not actually need the British any more, and increasingly UK physicists were shut out. Political tussles erupted between the two allies over who would take the lead.
By early 1942 there was no doubt. The US was unstoppable. After considerable wrangling, Roosevelt and Britain’s prime minister Winston Churchill struck the Quebec Agreement, a painstaking negotiation that set the ground rules for engagement between the two countries and established a joint project to find and buy uranium. The rules limited British access to the project, which meant that British scientists developed expertise only in certain areas. The Americans would not agree to continuing British involvement on any other terms. The Quebec Agreement allowed British scientists to travel to the US to continue fulfilling the promise of the Frisch–Peierls Memorandum, and atomic bomb building activities in the UK were effectively closed down. All efforts were focused on America. The full implications of the Quebec Agreement were felt later when the US pushed them away completely and the British found themselves only partially equipped to build their own atomic weapon.
The Manhattan Project had its beginnings in 1939 when Roosevelt established the Advisory Committee on Uranium. It became a military and political priority in August 1942 when it was transferred to the control of the US Army. The project was named after New York’s Manhattan Island, where a group of engineers had been recruited to construct some of the required infrastructure. A new top-secret laboratory, built on a desert mesa at remote Los Alamos in New Mexico, was set up to build the bomb. Many British scientists went there to brave the desert winds and fight against time to build a weapon never seen before. Other laboratories around the country, notably the Lawrence Livermore National Laboratory in California and Oak Ridge, built on a farm in Tennessee, joined the effort as well. In all, around half a million people ended up working on the Manhattan Project.
From 1942, General Leslie Groves, a gung-ho US Army officer, led the atomic bomb project. Groves chose a young American physicist, J Robert Oppenheimer, to head the weapons laboratory. It was a surprising choice because Oppenheimer was open about his leftist leanings – some even thought he was a communist – and throughout the entire time he worked on the project he was enthusiastically investigated by the notoriously paranoid Federal Bureau of Investigation headed by J Edgar Hoover.
Groves and Oppenheimer gathered together a team of physics brainpower the likes of which had never worked together before. Hundreds of thousands of physicists, chemists and technicians joined the effort between 1941 and 1945, including some of the greatest contemporary thinkers. Many were European scientists who had fled the rise of Nazism. Once the political differences between America and Britain were sorted out, largely through the 1943 Quebec Agreement, a significant number of scientists joined the Manhattan Project from the UK as part of the British mission, including William Penney and Ernest Titterton, later pivotal in the Maralinga story. Klaus Fuchs – another pivotal scientist for a different reason – also joined the effort.
Physics had always been an open science, where an international community of theorists and experimentalists shared their hypotheses and observations. The Manhattan Project, of necessity, could not operate like that. Its activities were totally secret. The results of the speeded-up experimental work could not be published in the scholarly literature; the work could not be discussed at international conferences; other laboratories couldn’t attempt to replicate the findings of researchers unless they were inside the tent. This secrecy rankled many scientists, and some refused to accept it. The more extreme became atomic spies. Others, such as Ernest Titterton, went the other way. Titterton relished secret work, as his later behaviour in Australia abundantly demonstrated.
Professor William Penney, another Manhattan Project physicist, was likewise comfortable with secrecy. His extensive background in secret wartime explosives and atomic weapons research equipped him to head the British nuclear tests in Australia. Penney was part of the small team who selected the targets for the Manhattan bombs, surely an onerous responsibility for a donnish mathematical physicist. He also visited Hiroshima after the bomb was dropped and conducted numerous scientific measurements on the ground.
In short, the Manhattan Project trained the men who later made the British bomb and brought it to the Australian desert. The huge covert project also taught them to keep their knowledge close. This ability to keep atomic secrets meant going against their scientific training. However, there is no reason to believe that these men (they were overwhelmingly men) were not sincere in their belief that the future safety of the world depended upon their ability to quietly and methodically change the nature of warfare.