Alfred Hitchcock originally planned to do his cameo as the body floating in the river. A dummy was even constructed to do the shot. The plans were changed and a female body, a victim of the Necktie Murderer, was used instead. Hitchcock instead became one of the members of the crowd who are listening to the speaker on the river bank. The dummy of Hitchcock was used in the typically humorous trailer hosted by Hitchcock.
This was the first movie that Sir Alfred Hitchcock shot in Britain since The Man Who Knew Too Much (1956), and his first entirely shot in Britain since Stage Fright (1950).
Alfred Hitchcock's daughter Patricia Hitchcock found this movie so disturbing that she would not allow her children to see it for many years.
Alfred Hitchcock's shooting schedule allowed filming to begin at 8 a.m. and finish at 6 p.m. every day while on location in Covent Garden in London. One day during filming, Hitchcock was in the middle of finishing a take when a union representative showed up to inform him that it was 6:15 p.m. and that they had to stop filming. Hitchcock became furious and threatened to walk off the set and film this movie back in Hollywood. After that, no more union representatives were allowed on the set.
This is the only Alfred Hitchcock movie to carry an "18" certificate in the U.K., or receive an "X" rating after the "X" age restriction was moved from sixteen to eighteen in 1971.
Alfred Hitchcock: In the opening scene of Sir George speaking to the crowd, Hitchcock can be seen at the rear of the crowd in a black bowler hat and dark suit. He's also visible as the crowd pushes together to get a look at the body that's washed up on the edge of the river.
Alfred Hitchcock: [identifying with the killer] An extended sequence involves following the killer's grueling task of retrieving incriminating evidence.
Alfred Hitchcock: [stairway tracking shot] The long tracking shot down the stairway while the murder is occurring.