What difference does winning the Perrier award make to a comedian's career? The short answer is, a lot.

The list of those who have won in the past is close to being a roll-call of the UK greats: Frank Skinner, Steve Coogan, Lee Evans, Jenny Eclair, Dylan Moran and last year Ireland's Tommy Tiernan.

The other connection between those names is that only Moran has brought a show to Edinburgh this year and even his had a run of only five nights, while most last the full three weeks.

The Perrier is like the ultimate graduation test for comics and once they have passed they rarely return to their alma mater.

Since his success in Edinburgh, Coogan has not returned with a show

Coogan is passing through Edinburgh only for a chat at the Edinburgh Television Festival, which is not open to the public.

He describes his position now as the "wise old fart" on the comedy scene.

"It's about seven years since I came here to do anything proper," he admits. That is the exact length of time since he won the Perrier award.

"I totally empathise with anybody starting out because when I was here I was petrified. I appreciate anyone who gets up there and puts their neck on the line.

"Nothing has really got me as excited as winning in Edinburgh. It's the atmosphere - it's the closest I'll ever get to winning an Oscar."

But given his praise for the city and its Festival, why doesn't he consider a return run? Simply, he is too busy with more profitable business, including two films he is developing.

"The only reason I'd come back would be for artistic reasons and since then [1992] I've buried myself in doing stuff for TV.

"I came to have a great time and further my career. If I hadn't won I probably would have come back.

"I might come back in a play one day."

'So much pressure to be original'

The only woman to have won the Perrier on her own - Emma Thompson was among the Cambridge Footlights group who took the award in its first year in 1981 - is Jenny Eclair.

Eclair has recently won a deal to write a novel, has produced comedy drama for BBC Radio 4 and is still touring the show Nosy Parker, which she put on at last year's Festival.

Jenny Eclair: Praises high standard of young comics

She too is only in Edinburgh to sit on the judging panels of other competitions and soak up the atmosphere.

"I didn't have time to knock together a new show," she says. "It would have been humiliating and embarrassing."

Eclair says the standard of acts by people just starting out in comedy had risen greatly during recent decades, partly as a result of prizes like the Perrier boosting expectations.

"People have to be better than they used to be when I was getting started in the early '80s," she says. "They see how people use the mic and acquire knowledge very quickly.

"There's so much pressure to be original. If you can say he's like so and so it's a bad thing.

"It makes me weep for my lost youth and enthusiasm. I can't just sit like a nappy in a drain clogging up the system."

Far from doing that, Eclair has recently won a deal to write a novel, scripted comedy dramas for BBC Radio 4 and is still touring the show Nosy Parker, which she put on at last year's Festival.

So it is true the Perrier is the ultimate stepping stone to fame and fortune?

"Only if you don't go mental, take drugs and fall over," she says.

"I'm very greedy. Greed and spite keep me going - plus a little bit of humility."