Although Mandrake was a character in the book 'Red Alert', his name was changed and in the book his character is 'Major Paul Howard'
CRIMINAL HISTORY:
Mandrake was an RAF officer and pilot during WWII until his plane was shot down and he was kept as a POW and tortured by the Japanese.
"Oh, well, I don't know, Jack, difficult to think of under these conditions; but, well... what happened was they got me on the old Rangoon-Ichinawa railway. I was laying train lines for the bloody Japanese puff-puff's."
BUSINESS:
Mandrake is an exchange officer from the British RAF who as of the events of the movie is working his 2nd year under General Ripper at Burpelson Air Force Base.
"Mandrake’s presence in the centre was due to the exchange scheme which
had long operated between the USAF and the RAF. It was a scheme
regarded with great approval by the authorities and even greater approval
by the participants."
MODUS OPERANDI:
Mandrake is truly the only sane or 'straight-man' character in this movie. Which I find interesting because in a movie where everyone is turned on by nuclear war, he is the only character that isn't and also the only character directly accused of being a homosexual ["I think you're some kind of deviated prevert"]. Mandrake isn't necessarily based on any historical figure in particular, however his voice and appearance might be inspired by Trevor Howard and Terry Thomas.
"Mandrake was a man of medium height and build. His uniform
was immaculate, with the four broad rings of a group captain on the sleeve
and a healthy display of decorations and campaign medals below his pilot’s
wings. His hair was long by USAF standards, but this was understood to be
an eccentricity which all RAF officers were prone to. His upper lip sported
a bushy and luxuriant moustache."
OTHER NOTES:
In the Dr. Strangelove novelization, Mandrake's face is describe as having "all the mournfulness of a disappointed walrus." And this is my favorite thing in the entire world.