Cask ale sales make up more of the UK beer market than previously thought, according to research by the Campaign for Real Ale (Camra).

The report, which was due to be launched today at the Great British Beer Festival in London, reckons that cask ale sales volumes have been under-reported by 17%.

Camra claims that factoring in the contribution of breweries eligible for small brewers' duty relief increases the size of the market from 2.5 million barrels a year to 2.9 million, meaning that cask ale makes up 13.1% of beer sold by the on-trade.

Mark Hastings, director of communications for the British Beer and Pub Association, agreed that some cask ale-producing breweries were doing well. "The key message here," he said, "is that if you get the product right and produce a quality beer with great promotion, you will grow your market."

He added: "We are currently seeing a renaissance in all types of beer. People are definitely coming back."