Director Jack Gold did not want Richard Burton and instead suggested Nicol Williamson for the lead role. The producers told him it would be easier to get funding with Burton, who had just made his "comeback" film Equus (1977).
According to trade paper 'Variety', "Apparently due to French financial participation in this film", the English Scotland Yard Detective character of Inspector Cherry from the film's source novel was changed to a Frenchman called Detective Brunel for this movie.
The film was made two years after its source novel of the same name by Peter Van Greenaway had been first published in 1975. The movie is the only ever theatrical feature film adaptation of one of Greenaway's books.
The Boeing 747 model used was a 9ft long former travel agents window model made out of perspex by Space Models of Feltham. The model was suspended 20ft above the floor of Shepperton Studios, for its 50 yard run to the Office block.
The tower block in the plane crash sequence was made out to be "Centre Point", a tower which had been empty since it was built in 1964. It still exists today by Tottenham Court Road and New Oxford Street. It is one of the tallest concrete towers in Britain (117m) and nominated as one of London's ugliest structures. It has been home to the Confederation of British Industry since 1980.
"The Medusa Touch" novel by Peter Van Greenaway was one of several of his books which featured the character of English Scotland Yard Inspector Cherry but the character didn't appear in this movie. Instead the character was a Frenchman called Brunel.
Some of the film's movie posters featured a text preamble that read: "TELEKINESIS: A mental force that enables this man to move objects and control events. Science cannot explain the awesome power of the mind. And nothing can control it. Richard Burton has THE MEDUSA TOUCH".
The cathedral in the climactic scenes was given the fictitious name of Minster Cathedral (even though it was intended to be Westminster Abbey) because the director did not want anyone who was familiar with the architecture of the Abbey to say "But that's not Westminster Abbey", given that the scenes were actually filmed at Bristol Cathedral.
The "Medusa" of the film's title refers to the famous monstrous character from Greek Mythology. Though an image of Medusa does appear in the film's trailer, the character does not appear in the film at all, its use is merely a metaphor, analogy or allegory. Medusa is mentioned at the beginning of the movie's trailer as well. The voice-over says: "In ancient legend, Medusa was one of three Gorgon monsters created to do battle with the gods. Anyone looking into the eyes of Medusa was instantly turned to stone".
The trivia items below may give away important plot points.
At the end of the film's source novel Morlar's hand scrawls the wording "Holy Loch" which was at that time the location of a US nuclear submarine base in Scotland. In the movie, the hand instead writes "Windscale".