The largest arts festival in the world launched its annual programme yesterday, detailing more than 2000 shows which will be performed at this year's Edinburgh Festival Fringe.

The programme includes the usual mix of controversial drama, comedy, dance, music and new theatre, with appearances by well-known names such as Brit Ekland, Ruby Wax, Clive James, and Joan Rivers, Jim Bowen, Simon Callow and Michael Barrymore.

Barrymore is appearing in Surviving Spike at the Assembly Rooms, a new play about Spike Milligan, a return to the celebrity spotlight after his appearance on Celebrity Big Brother in January, 2006.

However, yesterday's launch of the 62nd Fringe, which runs from August 3 to 25 came with an unmistakable sense of unease over its future and the looming presence of a new festival in the city.

At the same time as the Fringe launch in Edinburgh, the Edinburgh Comedy Festival, which describes itself as a "festival within a festival", was launched in London.

The comedy festival, which is the marketing collaboration of four of the biggest venues on the Fringe - Assembly, Gilded Balloon, Pleasance and Underbelly - has caused concern that the Fringe could splinter.

The four venues have combined marketing for their shows in a separate brochure, and are looking for a major title sponsor, in a deal which could be worth more than £1m.

Jon Morgan, director of the Fringe, said yesterday: "All the events within the Fringe do their own launches, and my feeling is that it all adds to the profile of the Fringe and that is good."

Mr Morgan also said that although the Fringe would provide some summer cheer for people suffering from the "credit crunch", he did not know whether it would affect the ticket sales at the event, which hit a record last year, selling 1.7 million tickets.

"The Fringe is always as big as it needs to be," he said. "There have been years where the amount of tickets have dropped, but the Fringe has continued. We shall just have to see how it is this year."

William Burdett Coutts, the founder of Assembly and one of the key movers behind the Edinburgh Comedy Festival, said the festival was "an absolutely natural development" for the Fringe and added: "We're attempting to take all the things that make the Fringe great, and make it better."

He said that many thought "comedy taking over the Fringe" is a negative development but he thinks it "the opposite".

About 32% of the shows in the Fringe programme are comedy, followed by theatre, which takes up 29%.

"In future years, we fully intend to open Edinburgh Comedy Festival up to all venues, artists and promoters that wish to participate," Mr Burdett Coutts said.

Charlie Wood, co-founder of Underbelly, said the official Thundering Hooves report - which warned of national and international rivals to the Edinburgh festivals - had "missed" that the biggest challenge to the Fringe was other summer festivals in the UK.

He said the levels of risk and deficit for venues were "increasingly unsustainable" and they needed to grow their audience and cut costs by taking a united route by raising sponsorship.

But Tommy Sheppard, who runs the Stand comedy club, one of the biggest venues in the Fringe, is resolutely against the new festival, and declined to get involved when it was mooted before Christmas.

"The question is why are they doing this? It was meant to lever in more money, but so far there is no major sponsor, not a penny in extra sponsorship," he said.."