Commander Fraser refers to his service medals as 'Squeak' and 'Wilfred'. These were nicknames for the the British War Medal and the British Victory Medal of the Great War. (Note: The 1914 Star and the 1914-15 Star star were nicknamed 'Pip'. The three names come from the names of characters in a Daily Mirror cartoon strip.)
The film is loosely based on the actual raid undertaken in 1942 by HMS Campbeltown, in which the ship, loaded with explosives, rammed and subsequently destroyed the dock gates at the French port of St Nazaire. This was the only dry dock outside of Germany able to accept and repair the German battleships Tipitz and Bismark.
The military mission in the film is based on the real World War II raid on St. Nazaire by HMS Campbeltown in a campaign known as Operation Chariot.
The so-called "Gift Horse" of the film's title refers to the nickname of the aged decrepit four-stacker ex-U.S. Navy destroyer seen in the film, the HMS Ballantrae.
This film's dedication states: "In 1940 when Britain was fighting ashore for her life, the United States transferred fifty of her destroyers to the Royal Navy. This picture is respectfully dedicated to their exploits and is very broadly based on the adventures of one of these destroyers."