On July 4, 1945, a select group of men met in a room in Washington, DC to decide how to use the first atomic bomb. Not all of them were Americans because the Bomb was not an American invention; use of the new weapon required approval from Britain, its co-inventor. For instance, the 1943 Quebec Agreement forged by United States President Franklin Roosevelt and British Prime Minister Winston Churchill specified joint development and control of atomic weapons.
The British Empire was the first nation to investigate nuclear explosives seriously. By 1941, the Brits had calculated the critical mass of fissionable material required for a bomb, worked out the basics of bomb design and the gaseous diffusion enrichment of uranium. All this information came to the United States with the "British Mission"—the team of top-flight British scientists who joined the Manhattan Project.
But America is not always a reliable ally, and British generosity wasn't reciprocated. General Leslie Groves, the tough, beefy chief of the bomb project, early on felt the weapon should be an exclusively American one and took steps to limit British access. As a result, America didn't share the method for extracting plutonium from uranium, nor did it reveal the existence of the massive Oak Ridge gaseous diffusion plant in Tennessee.
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Nevertheless, it was a huge shock when Foreign Secretary Ernest Bevin rudely learned his country's closest ally had no intention of sharing the Bomb. A shaken Bevin told Prime Minister Clement Atlee, "no Foreign Secretary should ever again be put in such a position," and Atlee agreed.
Though Churchill with his usual wit once dismissed Atlee as a modest man "who had much to be modest about," the Labor PM saw what many leaders have seen since—the only way to get taken really seriously as a major power was to possess the ultimate weapon. Despite Britain's exhaustion and near bankruptcy, she had to do whatever it took to arm herself with the atom. And she had to do it without any help from her friend.
Ironically Britain resorted to the tactics of its new foe, the Soviet Union. Klaus Fuchs, a smart, quiet, traitorous physicist who supplied Soviet agents with their most valuable materials on the U.S. effort, also aided his adopted country's weapons project. But the key figure in Britain's Bomb project, William Penney, had a more traditional sense of patriotism.
Penney excelled in hydrodynamics and designed floating breakwaters for the Normandy invasion. His abilities lifted him to the top of the Manhattan Project where he joined Robert Oppenheimer, John von Neumann and others making crucial decisions. Penney personally witnessed the Nagasaki attack, watching from an observation plane as the implosion system he helped create vaporized an entire city in one flash.
Penney became the "British Oppenheimer" on January 1, 1946, and later that year represented Britain during Operation Crossroads, the first American postwar nuclear tests. Though not formally asked to build a British bomb until May 1947 Penney had realized the job would likely fall to him. Shortly after his official appointment, he wrote out a general technical description of the Fat Man plutonium bomb from memory—a feat which gave the UK information equivalent to that which Soviet agents had stolen from America.
Britain faced the same pressures as the Soviet Union to get nuclear weapons as fast as possible. Wartime urgency drove the U.S. effort, but now need for "face" drove the British effort. America got the Bomb through its enormous resources, but Britain would have to duplicate that feat on a shoestring. These pressures—diplomatic and financial—would lead the UK to take dangerous shortcuts with frightening results.
To create the plutonium bomb fuel plant, production director Christopher Hinton chose a site on the northwest coast named Sellafield. Windscale, as the plutonium facility was known, became the largest construction project in the UK during the early postwar years. Hinton rejected the water-cooled reactor design used at the U.S. plant in Hanford, Washington, and instead chose air cooling. If the water cooling failed, thought Hinton, the reactor would overheat and catch fire.
After seven years of backbreaking effort, the first British nuclear device shipped out for Australia in September 1952. By then the Cold War had turned hot in Korea where British troops fought communist forces. The naval task force—the escort carrier HMS Campania , the target destroyer HMS Plym and some landing craft—left Portsmouth carrying the most expensive object ever produced in the Empire. The expedition's five ships and 1500 men seemed minuscule compared to the thousands of ships and men employed on the Crossroads tests.
The task force arrived at the Monte Bello Islands off Australia's northwest coast. On October 3, 1952, after the plutonium core was carefully lowered into the device aboard the Plym, all connections made, and the crews evacuated to a safe distance aboard the Campania.