Aaron Barschak sparked a security scare after gatecrashing Prince William's 21st birthday party, but he's not the first prankster to grab the headlines.

Nick Morrison looks at the peope who will do anything for publicity.

IT hasn't sold out yet, but tickets for one obscure act at this year's Edinburgh Festival Fringe are now going surprisingly well after a sluggish start. Or at least, it was an obscure act up until Sunday afternoon, when Aaron Barschak suddenly became the most sought-after performer at the world's biggest arts event.

And the reason everyone wants to see the self-styled Comedy Terrorist's act, titled Osama Likes It Hot, is not because he has a reputation for being side-splittingly funny, and in fact is nothing to do with the act itself. It is solely because Barschak, dressed as Osama bin Laden, gatecrashed Prince William's 21st birthday party on Saturday night.

As far as publicity stunts go, this is surely up there with the best of them, putting Barschak on a par with those who vault themselves into the limelight for no other reason than to be there. It's not to highlight the plight of starving orphans, or to bring attention to lax security - although Barschak's stunt hasn't exactly shown the police in the best light - but it is notoriety for the sake of notoriety.

Perhaps the most well-known practitioner in modern times is Michael Fagan, who broke into the Queen's bedroom in 1982, and indeed Fagan was summoned on to our television screens yesterday to pass comment on the latest breach in royal security. Fagan, a schizophrenic who spent four months in a psychiatric hospital following his palace break-in, spent ten minutes talking to Her Majesty after asking her for a cigarette, before security arrived.

Karl Power is probably Britain's greatest interloper, and his most famous stunt is being photographed alongside the Manchester United team before a match with Bayern Munich in 2001. He has also walked out to bat for England at Headingley, played on the centre court at Wimbledon, stood on the podium at Silverstone and danced the haka as the English rugby team walked onto the pitch in Rome.

While Power has achieved a certain level of fame - and has made money by selling photographs of his escapades - slightly less well-known is Jon Culshaw, who rang 10 Downing Street pretending to be former Tory leader William Hague, and was put through to Tony Blair, exchanging small talk until the ruse was discovered.

Slightly more dangerous was the stunt pulled off by Matthias Rust, who invaded Soviet airspace at the height of the Cold War to land his light aircraft on the edge of Red Square in Moscow in 1987.

"People do the most incredible things, and some of them do it for pure exhibitionism, such as the ones who streak across football pitches," says Dr Joan Harvey, chartered psychologist at Newcastle University. "Sometimes it is partly a dare, sometimes it is partly to see how far they can get, and sometimes it is partly to get 17 tonnes of publicity.

"This guy is going to be able to dine out on this story for months, and people will be queuing up to get into his show."

For Barschak, his prank meant a night in the cells and the ire of the police - although he is perhaps unlikely to be charged - and a good chance of a sell-out show, but the long-term effects may be harder to gauge.

"To some extent, some people just like notoriety, but I don't think they're always terribly well geared up to deal with it. Money can't buy the publicity he's got, but there's now the question of how well he can handle it," says Dr Harvey.

Joining Prince William on stage is apparently not the first of Barschak's stunts, although the others have gone largely unnoticed. He is said to have confronted former Monty Python Terry Jones during a tribute to Spike Milligan, and invaded shows by Eddie Izzard and Graham Norton. But, according to Barry Sudworth, psychology lecturer at Teesside University, the identity of his 'victims' may be largely irrelevant, raising doubts over whether it is really just about selling tickets at all.

"I'm not sure it is just a publicity stunt for his shows. You also have to look at why he is dressing up, and why he is wearing dresses, and why it is bin Laden," he says.

"We have someone who is craving attention, but is also hiding themselves behind a dress and a beard. He is standing up saying 'here I am' but he's not letting us know who he is. That, to me, suggests someone who doesn't really know himself.

"He needs to be identified, but he is not showing himself, and maybe it is because the real person is someone who is ignored or not taken seriously. It is interesting that the police pretty soon recognised he was not a threatening person and let him out on bail."

Mr Sudworth suggests that although Barschak is craving attention, because he is doing it by dressing as someone else, it may be that he is unhappy with who he is. If this is the case, then the resulting notoriety may not do him as much good as may be supposed.

"There is a degree of being unfulfilled, of wanting to be accepted but not knowing what he wants to be accepted as," he says. "So the actual result of this recognition may not do anything to improve his self-image. He is still regarded as a complete idiot."

Whereas those who gain attention through expected means, such as comedians who achieve fame because they're considered funny, may be in a better position to cope with the downsides, because at least they are in the spotlight for something they want to be in the spotlight for. But those whose claim to fame is the result of a publicity stunt may find it does not quite have the beneficial effects they had hoped.

They may sell a few more tickets, but it doesn't mean people will be watching them for their comedy.

This doesn't just happen to those previously unknown. You only have to look at how Anthea Turner suffered once she was seen as a publicity-desperate travesty who would sell her own wedding for attention, to recognise that fame for fame's sake is not all it's cracked up to be.

Of course, it's easy to read too much into what was, after all, a harmless prank. But the upshot is, that while there may be a few resignations among the police, the real loser could be Barschak himself. As the Fringe programme entry for the Comedy Terrorist's act suggests, for every "Spike would have loved it" (Sunday Times), there is a "W*nker" (Eddie Izzard).