SABMiller is buying London basedMeantime Brewing Company, snapping up one of the pioneers of craft brewing to give the owner of big brands such as Peroni and Grolsh exposure to a fast-growing part of the drinks market.

A surge in demand for craft beers in recent years has stolen market share from the world's two biggest brewers, SABMiller and Anheuser-Busch InBev, as consumers seek a more authentic taste and support niche, local suppliers.

Sales volumes of Meantime's beers, including London Pale Ale and London Lager, soared 58 per cent in 2014, compared with a one per cent rise in Britain's beer market as a whole.

Meantime was founded with the backing of a group of friends in a former tramshed in Greenwich in south London in 1999.

Supporters of craft beer say the brand risks losing part of its authentic appeal.

Meantime's chief executive Nick Miller, who joined from SABMiller in 2011, tried to fend off worries that the company was selling-out.

"SABMiller shares our passion for putting great beer first, and making, selling and marketing it responsibly to beer aficionados worldwide," he said.

Meantime's founder Alastair Hook, its brew master, and Mr Miller will continue to be part of Meantime following completion of the deal, which is expected in early June.

SAB said it planned to grow the sales of Meantime's beers across Britain and would also look to export it to other markets in Europe.

SABMiller's US joint venture with Molson Coors, MillerCoors, already sells Blue Moon in that country, another beer that plays in the craft beer category, though its real craft credentials are often questioned.

AB InBev bought Goose Island, another US craft beer brand, in 2011.

Craft brewery founder Jeff Rosenmeier, whose Lovibonds brewery is based in Henley-on-Thames, southern England, questioned whether Meantime's beer could still truly be called craft.

"I probably won't be drinking Meantime anymore," he said.

The financial terms of the deal were not being disclosed.

"The variety of styles added to SAB's extensive local and heritage beer menu should serve it well," Accendo Market's Mike van Dulken said.