This film is based on the real-life Royal Navy cadet George Archer-Shee (1895-1914), the alleged theft took place in 1908 and the trial in 1910. Archer-Shee was commissioned in the British Army in 1913 and was killed in WWI at the First Battle of Ypres on October 31, 1914.
H.H. Asquith, the Prime Minister whose name is mentioned several times throughout the film, was the father of the film's director Anthony Asquith.
Neil North who plays Ronald -the Winslow boy - in this 1948 version also plays in the 1999 remake of the film, but this time as the First Lord.
The film's screenplay adds the trial scenes, which all take place offstage in the play. The role that Francis L. Sullivan plays was added for the film.
Robert Donat's character Robert Morton is based on Edward Carson (1854-1935) who took the defense in the Archer-Shee case. He became famous by defending the Marquess of Queensberry against Oscar Wilde's libel suit in 1895. Since he announced in the trial's opening speech that he would produce male prostitutes as witnesses, Wilde was forced to withdraw his claim and pay damages to Queensberry which bankrupted him.