Bond's superior 'M' is thought to be largely based on Fleming's wartime NID chief John Godfrey — one of several contenders

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Ian Fleming served as personal assistant to John Godfrey — Director of the Naval Intelligence Division (NID) from February 1939 to November 1942 — in NID's Room 39, working under the wartime code name 17F. Per History.com (Greg Daugherty), which notes "there are several contenders for the title of M's real-life model," Godfrey is the one M is "thought to be largely based on" — an attribution the article states in its own voice, naming no underlying source for it. Fleming and Godfrey together produced the 1939 "Trout Memo," a list of deception ploys later drawn on for Operation Mincemeat — one direction of the same office's fiction-tradecraft loop that runs, in the other direction, from that office's wartime work back into the Bond novels themselves.

This formalizes, with a dedicated source and quote, an attribution the vault had previously carried only as an aside inside Godfrey's DNI-tenure note ("Godfrey is widely described as an inspiration for Ian Fleming's fictional 'M'"), which cited no source specific to the M-attribution itself.