Underworld (also called Transmutations) is a 1985 British horror film directed by George Pavlou, written by Clive Barker and James Caplin, and starring Denholm Elliott, Nicola Cowper, Steven Berkoff, Larry Lamb, Ingrid Pitt, Irina Brook and Art Malik.

[1] Dr. Savary (Elliott), a sinister biochemist, has created a subhuman species that dwells in the London Underground.

The victims' only hope for an antidote lies in kidnapping Nicole (Cowper), a high-class prostitute.

Roy Bain (Lamb), a fearless adventurer and Nicole's former lover, is hired to save her.

After a quick cinema run in the UK, the film was given a limited release in the United States by Empire Pictures in April 1986.