Another intriguing moment. John Cockcroft was a lynchpin of the British reactor efforts from wartime until the early 60s. Ben Lewis ditto for the Canadian reactor efforts (although his influence waned by the 60s). I spotted a handwritten letter from the latter to the former that suggests to me that Cockcroft was fishing for a successor (something his biographers make plain) and that Lewis rejected him. How might history have progressed in an alternative scenario? (I don’t have Cockcroft’s initiating “personal note,” nor have I seen anyone else mention this exchange.)

In reply to your personal note of 22 March I think it would be a mistake to encourage the Executive Committee to think of me as possible successor at Harwell in 4/5/6 years. … So I don’t say no, but it is highly improbable that I would accept a move to Harwell.
Lewis, W. B. 1954. Lewis to Cockcroft, Mar. 28, 1954. AB 27/8. National Archives, Kew, United Kingdom.