As the war progressed, the sheer cost and vulnerability of building massive enrichment plants in the UK became prohibitive due to German bombing. In 1943, Churchill and Roosevelt signed the , which integrated British scientists into the American "Manhattan Project." However, this partnership was never truly equal:
As the project neared success, the U.S. began to restrict British access to key data, fearing post-war commercial competition and Soviet espionage. The Post-War Freeze: The McMahon Act Churchill's Bomb: How the United States Overtoo...
Left out in the cold, the British government decided they could not afford to be a second-tier power. In 1947, they began their own independent program, eventually detonating their first atomic device in 1952. By then, however, the United States had already moved on to the Hydrogen Bomb, cementing its status as the world’s lone nuclear superpower for a time. As the war progressed, the sheer cost and
The ultimate "overtaking" occurred in 1946 with the passage of the . This U.S. law cut off all international cooperation on nuclear energy, effectively locking Britain out of the very project it helped start. Churchill felt betrayed, as he believed the "Special Relationship" guaranteed Britain a seat at the nuclear table. The Result: An Independent Deterrent The Post-War Freeze: The McMahon Act Left out