Grodmannen som försvann: Lionel "Buster" Crabb, Portsmouth harbor, England, 1956.

In his statement Sir Anthony told MPs: "It would not be in the public interest to disclose the circumstances in which Commander Crabb is presumed to have met his death.

"While it is the practice for ministers to accept responsibility, I think it is necessary in the special circumstances of this case to make it clear that what was done was done without the authority or knowledge of Her Majesty's ministers. Appropriate disciplinary steps are being taken."

In his statement Sir Anthony told MPs: "It would not be in the public interest to disclose the circumstances in which Commander Crabb is presumed to have met his death.

"While it is the practice for ministers to accept responsibility, I think it is necessary in the special circumstances of this case to make it clear that what was done was done without the authority or knowledge of Her Majesty's ministers. Appropriate disciplinary steps are being taken."

http://en.wikipedia.org/wiki/Lionel_Crabb

MI6 recruited Crabb in 1956 to investigate the Soviet cruiser Ordzhonikidze that had taken Nikita Khrushchev and Nikolai Bulganin on a diplomatic mission to Britain. According to Peter Wright in his book Spycatcher (1987), Crabb was sent to investigate the Ordzhonikidze's propeller — a new design that Naval Intelligence wanted to find out more about. On 19 April 1956 Crabb dived into Portsmouth Harbour and his MI6 controller never saw him again. Crabb's companion in the Sally Port Hotel took all his belongings and even the page of the hotel register where they had written their names. Ten days later British newspapers published stories about Crabb's disappearance in an underwater mission.

[...]

A little less than 14 months after Crabb's disappearance, on 9 June 1957, a body in a frogman suit was found floating off Pilsey Island in Chichester Harbour. It was missing its head and both hands, which made it impossible to identify (using then-available technology).[2] The body had the same height as Crabb, the same body-hair color, and was dressed in the same clothes, Pirelli two-piece diving suit and Admiralty Pattern swim fins that Crabb was wearing when he embarked on his final mission.[2] The British diving expert Rob Hoole wrote that given the length of time that Crabb's body had been in the water, there was "nothing sinister" about the missing head and hands.[2] Crabb's ex-wife was not sure enough to identify the body, nor was Crabb's girlfriend Pat Rose, though Sydney Knowles said that Crabb had had a similar scar on the left knee. An inquest jury returned an open verdict but the coroner announced that he was satisfied that the body was that of Lionel Crabb.

In one scene in the latter part of the story, Hergé included a frogman, whose depiction was drawn from a press clipping of Lionel Crabb.

Bond's examination of the hull of Disco Volante was inspired by the ill-fated mission undertaken on 19 April 1956 by the ex-Royal Navy frogman "Buster" Crabb on behalf of MI6, as he examined the hull of the Soviet cruiser Ordzhonikidze that had brought Nikita Khrushchev and Nikolai Bulganin on a diplomatic mission to Britain. Crabb disappeared in Portsmouth Harbour and was never seen again.