Classical music festivals are booming in the United Kingdom - but promoters warn strong ticket demand does not always lead to big profits.

"Practically every town and village in the U.K. has its own festival," cellist Julian Lloyd Webber says, though exact figures for the number of outdoor and venue-led festivals are not available.

"From an artist's perspective, it means you can reach a different and wider audience than you normally would," says Lloyd Webber, who is opening Birmingham's third annual New Generation Arts Festival in June. "But they can be so costly. If you use a full symphony orchestra, for example, costs rise dramatically."

Festival organizer Birmingham University says it "just about covers costs," despite sponsorship deals. In addition, attendance at the 2007 festival tripled year on year to 150,000 visitors, according to the official festival report.

Melanie Moult who manages guitarist John Williams and violinist Thomas Zehetmair, agrees that the festival boom is good news for artists.

"The classical music festival circuit plays a vital part in any artist's performance schedule," she says. "It's wonderful that more artists are leading festivals, as they have the most valuable insight, experience and knowledge."

But even the bigger, more-established events can struggle to turn a profit.

Anthony Whitworth-Jones, general director of Garsington Opera, the prestigious month long opera festival held in Oxfordshire, England, since 1989, says the event is experiencing "higher demand for tickets than ever, due to more and more people embracing live music."

But he adds, "Classical music festivals just don't make money. Especially with opera - it's very labour-intensive, a huge amount of technical skill is involved, there are several people onstage at once, and that costs a lot."

Garsington gets 18% of its income from trusts and foundations, 22% from fund-raising, 56% from box-office receipts and the rest from advertising and catering, Whitworth-Jones says. More than 12,500 people each season attend the festival and pay 80-135 pounds per ticket.

"But we just couldn't charge what it would actually cost to make a profit," Whitworth-Jones says. "Without donations we would be looking at 250 pounds each."

Yet festival entrepreneurs continue to set up new events, often making ends meet through an innovative mix of private and public sponsorship.

Svend Brown, artistic director of the East Neuk Festival in Fife, Scotland, funds his event through financial support from the National Lottery and the Scottish Arts Council, as well as private sponsors.

"Finding private donors is the hardest part," Brown says. "Public subsidy just isn't enough."

Andrew Lucas, executive organizer of the annual Lake District Summer Music Festival, established in 1984, says that - despite 2007 sales of 10,000 tickets priced between 3 and 17 pounds - just 23% of the festival's 2007 income came directly from attendees, Corporate income accounted for 4%, a clear indication of room to grow.

Lucas calls for the sector to "become more commercially savvy," noting that funds should be boosted by next year's introduction of a major hospitality program for corporate visitors.

"Sponsorship proves there is private interest in the arts," festival marketing manager Cliff Dixon says. "We need to expand into hospitality, catering and other ways of making money privately, aside from music."