The first movie of Rialto's Edgar Wallace series to be shot entirely in England, both on-location and in the studio. All former movies has been shot in Germany with insert shots and archive footage of London used to create a more "British" atmosphere. Archive footage from this movie was also used in Edgar Wallace movies.
The German and English versions were filmed simultaneously in London.
According to various sources, this was the first co-production between West Germany and the United Kingdom after World War II.
Sir Christopher Lee was married to his wife Gitte just before production began. They had no time for a full honeymoon as they only had a weekend before filming began on Mondy. They spent it in Brighton and resolved to have a serial honeymoon spread out over the next year between movie commitments.