Real tube nightmares

"We used Camden for a scene in which Franka runs past a lot of shelves loaded with boxes of documents," recalls Smith.

"The shelves weren't really shelves, though - they were bunk beds used by American GIs during the war. They slept on them on the night before D-Day." (If you fancy a look at the entrance to this tract of subterranean history, stand in the car park of the Underhill Street branch of Marks and Spencer, and look for a pair of blast-proof doors.)

"The great thing about the Tube as a location," says the director, "is that you're completely isolated from the outside world. It's like the Poseidon Adventure or Alien. You might as well be in outer space or at the bottom of the sea."

His voice drops ominously: "And you're never far from death on the Underground. When you're on the platform there's only a thin yellow line between you and electrocution. We all have to trust the people standing behind us."

Smith had his own brush with death during the shoot. When Sean Harris, playing the villain, walked on to location in his full special-effects make-up, the director was so pleased that he accidentally stepped back onto the track. A gaggle of London Transport officials yelled at him to move. Less than a minute later, the power was switched on automatically, and electricity flooded through the line.

SMITH has been itching to slake himself in gore since childhood. "When I was six or seven I used to sneak downstairs and watch the Hammer horror movies," he says. "Then I graduated to the early Eighties video nasties. Halloween and The Texas Chainsaw Massacre were my favourite films when I was a kid. I always knew that when I made a movie myself I'd do something really twisted."

After graduating from Bristol University's MA film production course in 1998, Smith cut his professional writing fangs on EastEnders. He was given the job of nurturing the relationship between Kat Slater and Dr Trueman - a story arc known to the soap's producers as the "Madame Bovary plot".

Since then, he has been pushing an unfilmed gangster script through the painful process of development ("it came too late," he laments), directing documentaries for the Universal Studio Channel, and producing Barry Norman's film review show on Sky. Then, in 2003, along came the deal that brought Creep into being.

It is a film, he hopes, that points the way towards a revival in the fortunes of the British horror picture. "We've always been good at horror in Britain, right back to Mary Shelley and Frankenstein. I think there's not just going to be a wave of horror movies, but it's going to become our staple diet again. Films like Shaun of the Dead and 28 Days Later - they were made by people who grew up obsessing over British horror movies."

And if any other aspiring horror director wants to explore the nasty possibilities of the Underground, then Transport for London, it seems, will be only too happy to help out - provided the script is sufficiently bizarre.

"If it had been about a group of terrorists taking over the Tube," says Smith, "there's no way they would have let us do it. But nobody's really going to think that if they get on the train to Cockfosters they're going to get put in a cage and tortured."

Absolutely not. Unless some mischievous journalist puts an idea in someone's head ...