The 85-seat Brighton restaurant, the Gourmet Burger Kitchen chain's first outside London.

The 85-seat Brighton restaurant, the Gourmet Burger Kitchen chain's first outside London.

A restaurant chain founded by three New Zealanders is turning into one of Britain's most successful new food businesses - a year after the Kiwis sold out for £10 million ($25.7 million).

Under new owners Clapham House Group, Gourmet Burger Kitchen, based on "relaxed Kiwi-style dining", is being rolled out across London and Britain at a breakneck pace. Clapham House, an umbrella company for restaurant chains, has ambitions to turn GBK, as it is popularly known, into the leading up-market burger eatery in Britain.

GBK was established six years ago by Greg Driscoll, Brandon Allen and Adam Wills, all of whom went through school and university together in New Zealand.

Since buying the company outright from the trio, Clapham House has rapidly increased the number of outlets. In April, it opened two more in London and will this year expand into Scotland.

Clapham House is so impressed by the brand's potential that it is looking for 100 more sites across Britain.

It is largely the success of GBK that has attracted investment banks and other institutional shareholders to the share register of Clapham House, which is listed on the London exchange's junior board, AIM.

The company has found that new outlets generally pay their way almost as soon as they open.

"GBK restaurants are profitable from day one," said chief executive Paul Campbell, a veteran of the restaurant trade. "And this has been the case both inside and outside Greater London."

So encouraged is Clapham House that it has raised another £4.5 million through the issue of new shares "to accelerate the roll-out".

Since the start of the 2006 financial year, Clapham House has added 13 GBK outlets including ones in Britain's hottest tourist spots - St Paul's and Covent Garden - as well as the first outside London, an 85-seater in Brighton.

Using the cash generated by the outlets, the company has just opened two new restaurants - in Greenwich and Walton-on-Thames - and will shortly launch three more, in Cambridge, Notting Hill and Lakeside. A further seven are in the pipeline.

By the end of the year, Clapham House will have more than tripled the size of the chain from the six outlets it acquired in November 2004, with a down payment of £2.6 million. The New Zealanders stayed on for 18 more months before cashing out.

The runaway growth has occurred in one of the most competitive retail commercial markets as Britons rush affordable restaurants in a general "flight to quality" in fast food. In what is known as the "posh burger" market, GBK is up against competitors such as The Burger Company, Hamburger Union and Ultimate Burger.