Good Lord! This is really surprising. The history books all assume that Gibson flew into the ground, possibly suffering from exhaustion.
He was certainly an interesting character: not the peerless knight sort of leader, and perhaps he would have been unremarkable had it not been for the war, which tended to obscure some of his less pleasant characteristics. Given the damage done to so many survivors of the Allied bombing campaign, perhaps he was one of the lucky ones, to die leaving such a legacy.

Confession reveals friendly fire killed hero of WWII Dambusters raid
Sarah Rainey
The Sydney Morning Herald
12 Oct 2011

LONDON: Guy Gibson, the pilot who led the Dambusters raids during the Second World War, was shot down and killed by mistake by one of his own men, it has been claimed. Wing Commander Gibson, who led 617 Squadron in a series of daring raids over…read more…