Dir: Bryan Singer. US. 1999. 96 mins.

Prod co: 20th Century Fox, Marvel Entertainment Group, The Donners' Company/Bad Hat Harry. Dist: Fox. Prods: Lauren Shuler Donner, Ralph Winter. Exec prods: Avi Arad, Stan Lee, Richard Donner, Tom DeSanto. Scr: David Hayter. DoP: Newton Thomas Sigel. Prod des: John Myhre. Ed: Steven Rosenblum, Kevin Stitt, John Wright. Music: Michael Kamen. Main cast: Patrick Stewart, Hugh Jackman, Ian McKellen, Halle Berry, Famke Janssen, James Marsden, Bruce Davison, Rebecca Romijn-Stamos, Ray Park, Anna Paquin.

Based on what is reportedly the best-selling comic book ever - $400m worth of sales worldwide since it was created in 1963 by Stan Lee - X-Men has a huge and furiously loyal built-in audience. However, to become a real (and, for Fox, very welcome) summer blockbuster the film needs to appeal beyond that core fan-base. X-Men the movie is dark and sometimes relatively slow-moving; but, as stylishly directed by Bryan Singer (The Usual Suspects, Apt Pupil), it has enough enthusiasm and heart to fulfil its immediate box office task and, perhaps, form the basis of an on-going franchise.

The first hour provides a prologue to the X-Men mythology and introduces the brooding X Men - and Women - themselves. In the near future, evolution has produced a small minority of "mutants" - human beings with extraordinary powers. Picked on by politicians and public alike, the mutants divide into the enlightened followers of telepathic Xavier (Stewart), a believer in human-mutant harmony, and the aggressive henchmen of heavy metal-wielder Magneto (McKellen), who advocates any means necessary for the survival of mutant-kind. The film takes its time in setting up the two camps, but the process helps establish a connection with the characters, especially Wolverine (Jackman) and Rogue (Paquin). Effects are used sparingly but effectively.

The final half-hour is more conventional summer fare. To its credit, though, the film never lets the effects dominate the story and builds gradually to a satisfyingly intense climax. The last scene prepares the way for what Fox undoubtedly hopes will be a blockbuster sequel.