As the title says: what, if anything, did Churchill know about the Manhattan Project at that point in WWII? I know that there were British people involved in the project, but I don't know what the upper echelons of British government did or didn't know about the project at that point.
I'm asking because we discussed in class today Churchill's frustration with FDR's practically giving away the farm to Stalin during the Tehran Conference, and I wondered how much his knowledge (or lack thereof) of the secret work of the Manhattan Project may have influenced his opinion. My professor wasn't sure what, if anything, the British government knew of the U.S.'s atomic development at the time, so I thought I'd ask here.
By late 1943 Churchill not only knew about the Manhattan Project but had already negotiated that the UK be let in on it as an equal partner (the Quebec Agreement was concluded in August 1943, a few months before Tehran). Churchill himself was directly involved in this and it had followed many months of him personally discussing the matter not only with his own advisors, but personally negotiating with American officials and scientists, and of course Roosevelt himself.
So Churchill would have known as much as anybody about the prospects of nuclear weapons in November-December 1943. It should be noted that the bomb was still relatively far away at that point, however; the project was still getting off the ground (it was about halfway through its main "construction" phase, and the "operations" phase was just starting up), and what kinds of weapons might be produced was still very much unclear.
The most accessible and detailed account of Churchill's own role in all of this is Farmelo's Churchill's Bomb.