On a mission to study Halley's Comet, the space shuttle Churchill encounters an alien spacecraft. Inside are strange bat-like creatures and three naked, perfect humanoids. When the Churchill returns to Earth without contact, a rescue shuttle finds the crew dead, but the naked strangers untouched by the fire that ravaged the ship. Then the female alien starts to steal the lifeforce from humans around her, turning them into life sucking zombies.

LIFEFORCE may be the most bonkers film ever to be marketed as mainstream science fiction and is certainly emblematic of 1980s excess. There's a gorgeous space girl who spends virtually her entire screen time buck naked. There's giant vampire bat monsters. There's body-jumping alien spirits. There's people turning into desiccated zombies and then coming back to life two hours later to turn other people into desiccated zombies or simply to explode into ash. There's bodies that stream blood into the air so it can form the shape of a woman. There's Patrick Stewart's first screen kiss and it's with Steve Railsback. There's staking people through the heart (all right one or two inches below the heart, but that's close enough) and a trip to an almost Victorian asylum. It is, in short, utter insanity and it's hard to understand how anyone ever thought it was a good idea at the time.

Which explains why it has become a cult favourite over time, despite its initial failure. Nothing succeeds like excess, but sometimes it can take a while to be appreciated.

Which is not to say that LIFEFORCE is all bad. It's got quite a good cast. Peter Firth works hard to try and anchor the film with his no-nonsense SAS Colonel, not quite taking everything in his stride but certainly with an eye o f what has to be done at any given moment. He makes an interesting double act with Steve Railsback, who starts off at eleven on the intensity scale and finds he has nowhere to go from there. Frank Findlay is quietly imperious as the student of death and Patrick Stewart does some really good screaming. And then there's Mathilda May. Much has been made of the unnecessarily extensive nudity she is subjected to, but she manages to project the otherwordliness of her character through her movement. Much more so than through her very sparse dialogue.

Moments of humour manage to puncture the madness with Carlsen fighting off an arm freshly ripped from a zombie and the Prime Minister sneaking his secretary off to a side room to suck her life energy out, but the whole piece is played at such an intense level that those moments are few and far between. The plot bounces between the space opera opening, to the zombies to a search for a body-hopping killer to the devastation of London, and all in under two hours. You might be amused, appalled or just confused, but you will definitely not be bored.

Some of the creature effects are a bit poor, as are some of the space shuttle effects, but that almost plays into the off-kilter charm of the film as a whole. Director Tobe Hooper ramps up the more gruesome effects as London is overrun by more and more zombies, amping up the horror aspect.

LIFEFORCE is one big, mad mess of a film, camping it up and having a wonderful time shooting off in all sorts of directions. It's either so bad that it's good, or it's just bad, but that's for the audience to decide.