Yo fui el doble de Montgomery

The screenplay omits David Niven's part in the real operation. It was he, working for the Army's film unit as a Lieutenant Colonel, who first made contact with M.E. Clifton James. His role is taken in this movie by Major Harvey (Sir John Mills).

Soldiers refer to the Queen's Regulations, whereas at this time they should be the King's Regulations (King George VI).

The story you are about to see is the story of one of the boldest deceptions of our time in which Meyrick Clifton James, late of Her Majesty's Pay Corps, re-enacts his own real-life role. The Producer is deeply grateful to H. E. The Governor and Commander-in-Chief and those member of the Administration and Services at Gibraltar in March 1958, who rendered their invaluable assistance in the reconstruction of certain scenes of this film.

Referenced in Los vengadores: Epic (1967)