One of the main hubs of the Edinburgh Festival Fringe, the Assembly Rooms, will cease to be a key venue after 2010, its promoter warned yesterday.

Bill Burdett Coutts blamed Edinburgh City Council for threatening his 30-year link to the historic property by going ahead with a £12m revamp.

The authority is planning to redevelop the council-owned listed building on George Street, with its ground floor turned into areas for shops, and a "fine dining" restaurant taking the place of its current bar. Work is expected to start in September 2010 and take 22 months to complete.

Questions were raised last year about what was then thought to be a short-term refurbishment of the Assembly Rooms, but the council has now spent £500,000 on design plans and Mr Burdett Coutts said that the proposed changes would leave the venue unsuitable for use as his main Fringe theatre.

He plans to pull out of staging shows there, ending three decades of using the venue for Fringe productions, and place comedy acts elsewhere in the city.

Mr Burdett Coutts said: "If (the work) goes ahead, I won't be here. If they do go ahead with it, I don't see the point in carrying on. It would be better that I stop.

"It would, in my view, be a tragedy. This is a unique building and a unique venue, but if it ends in 2010, then that is my 30 years up. I think it would be devastating for the Fringe.

"I don't think the council will listen to me because they think I am being difficult.

"It is strange, because I think that Edinburgh City Council does not engage with the Fringe, there seems to be a barrier between the Fringe and the councillors and I don't know why."

Last night, a spokeswoman for the council said an announcement about the future of the scheme would be made soon. She said that "the proposals state that most of the Rooms will operate as an arts venue despite the changes, so there is no question about it not being suitable as a Fringe venue".

Mr Burdett Coutts has leased the venue for the Festival every year and, under his artistic control, it has become one of the "big four" venues of the Fringe, along with the Gilded Balloon, the Pleasance and the Underbelly.

The quartet have controversially marketed themselves as a separate Edinburgh Comedy Festival this year, although one of the prime aims of the venture - to find a commercial sponsor - has yet to be achieved.

Mr Burdett Coutts said that such a sponsor, who it was hoped would pay around £1m for the privilege, was unlikely to be signed this year - and may not be found for the next Festival.