Fact or fiction. Will the real Brett Allen please stand up?

"Brett Allen is innocent" the billboards have been screaming - yet another miscarriage of justice, perhaps, a man wronged?

The name has been emblazoned on buildings all over the country much to the bemusement of Brett Allen, the student from St Albans in Hertfordshire, who has become entangled in a promotional campaign for a new novel.

Yesterday, the real Brett Allen came face-to-face with the publisher of a book whose advertising campaign takes his name in vain.

"Who is Brett Allen?" he asked the marketing director of Random House. "It's a fictional character - a woman," came Mark McCallum's reply. "Is there a real Brett Allen?" he continued. "Somebody's cousin is actually called Brett Allen," replied Mr McCallum, faintly amused.

"Apparently they are being driven crazy by seeing their name up everywhere. We've gone for it big time - to raise the profile of the author."

"I wouldn't like to be the real Brett Allen!" exclaimed the real Mr Allen. Mr McCallum agreed. "He was supposed to be saying his life has been made a misery by this," he remarked casually.

Mr Allen had come to London to clear his name. Posters have been plastered on walls outside law courts, police stations and railway stations to give the impression of a subversive prisoner-protest campaign.

The words were beamed into the sky for the whole of London to see and crime correspondents were anonymously urged to take up the case.

Yesterday it was revealed that it was all part of a Saatchi and Saatchi campaign to promote The Final Judgement, in which a woman called Brett Allen is accused of murdering her boyfriend.

But in raising the profile of their best-selling American author, Richard North Patterson, Random House has inadvertently trodden on the toes of the 20-year-old psychology graduate with the same name.

"Obviously I want to disassociate myself from it. Because I'm an honest guy I don't really want anyone to mistake me for being a criminal," he said.

He first heard about the campaign from his uncle who had seen a poster at Waterloo station. "I thought he was winding me up at first - but then he sounded quite serious. My dad was concerned," he said.

"If it had been `Brett Allen is great', or `Brett Allen is cool' I wouldn't have minded that. Or even `Who is Brett Allen?' - that would have been OK."

While Mr Allen hopes that it will work in his favour, his brush with fame has already alerted him to its price. "I've had calls from people who I don't know. You look at the colour display and it's a withheld number. It becomes a bit sinister."

And the paranoia has begun to creep in. "I'm kind of worried that to a certain extent it's some kind of premonition for the future," he said.

"I'm a little superstitious. It could come true. That's lurking in the deep recesses of my mind."

Saatchi and Saatchi was delighted to hear of Mr Allen's existence. "I do think it's an excellent twist that there's a real Brett Allen out there," said a spokeswoman for the advertising agency. "It's quite amazing that it's affected him enough to call you. Obviously the campaign must be provoking some interest."

And when Mr McCallum heard that he had in fact been speaking to the real Mr Allen, he was surprised at "the likelihood that ultimately someone had the time even to say, `Hey, that's me'."

He dismissed any suggestion that Mr Allen may suffer from the publicity. "I really would be very surprised if it had any particular impact on his life," Mr McCallum said.