Why settle for Michelin stars when you can have a restaurant empire? Vanessa Thorpe talks to the chefs who think big
Every day Jean Christophe Novelli clambers aboard his moped, checks his mirror and speeds across London to call in, one by one, on each of his four restaurants.

"I have a need to be crazy," says the chef. "I am hyper. I am condemned to be like that. In one day I start at Novelli W8 and then I go to Les Saveurs in Mayfair and then I go in 10 minutes to Maison Novelli in Clerkenwell and then I go to the Novelli EC1 and then to cook at Les Saveurs and then I go back to EC1. And about once a month I go to my restaurant in Cape Town."

With his speedy bike, Novelli, well known for being at the cutting edge of food fashions, is now the most extreme example of the one of the most notable trends in cooking. Many of Britain's most famous chefs are no longer happy with one restaurant in which to display all their creative skills. Now they want to brand themselves with a series of eateries.

Celebrity chefs such as Antony Worrall Thompson, Marco Pierre White and Raymond Blanc enjoy so much acclaim that they are able to build up gastronomic empires at the drop of a bain-marie.

Soon it will be impossible, even at the very best restaurants, to know for sure that a genius - rather than a hired underling - has overseen the arrangement of the crescent of wild mushrooms on your plate.

The expansionist trend became firmly established in London last summer when Michelin-starred Marco Pierre White accepted an astonishing seven hotel-restaurant deal to crown his stewardship of Quo Vadis and The Criterion. Since then his bid for domination of the capital has been challenged by the 36-year-old Novelli and, on a smaller scale, by Alastair Little and Stephen Bull.

Dashing a few miles between different London venues might just be possible, but the chefs are now branching out to such an extent that they are opening restaurants in their name hundreds and even thousands of miles apart. Novelli, for instance, has another in Normandy and even one in South Africa, while Raymond Blanc has just opened a branch in Cheltenham.

The trend has appalled die-hard traditionalist chefs, and foodies too, who fear that quality can only be diluted by such franchising. Gourmets are wondering what can be happening to haute cuisine when one of the masters, Raymond Blanc - the man behind the legendary Le Manoir aux Quat' Saisons in Great Milton, Oxfordshire - is happy to become a brand name.

One critic of the trend, the television chef Anthony Tobin, who runs The Dining Room in Reigate, Surrey, warns that an eminent presence in the kitchen of a top restaurant is part of "a tacit bargain made with the patrons".

But in these days of the chef-as-showbiz-star, the crowds seem to love expansion. Take Blanc's opening of le Petit Blanc in Cheltenham. Four teenage schoolgirls from a nearby convent slipped out of their building, jumped over the wall and ran straight into town to attend the ritzy launch party for Blanc's pounds 850,000 establishment.

That was one evening when you could guarantee Blanc would be in attendance. "These girls were amazing, so determined," he recalls. "The whole launch was absolutely amazing, in fact, especially when you think this place is supposed to be full of retired generals. We were packed out with people who love food."

Blanc was the last man that hard-line foodies expected to be seduced in this way.

"You can hardly accuse me of being imperialist," Blanc protests. "I have had many, many opportunities, but until now I have refused them categorically. For 14 years I have resisted all sorts of temptations. I knew that if I left the kitchen I would lose my heart, my core."

He insists that the recent birth of his two Le Petit Blanc brasseries, the first in the centre of Oxford last June, is a different thing altogether. "We don't intend to do a chain. It would be too boring. We just want them to be the best of their type."

Yet Blanc will admit that he is keeping an eye open for other suitable sites for the brasserie project, which is a joint venture with Richard Branson and Forte.

"We are being much more businesslike than ever before. When I opened another restaurant in Oxford 10 years ago I had a glorious kind of failure. We became much too good," he says, with customary chef-like modesty. "This time we will simply offer quality and value and I will stay in my kitchen at Le Manoir."

This means that visitors to all future Petit Blancs will be paying for the Blanc concept rather than for any direct involvement from the great man himself.

Jean Christophe Novelli, whose venues have all opened up within the past two years, says he knows that becoming bigger is making him more vulnerable to criticism about the lowering of standards. His salvation, he believes, is in the hands of his staff.

"I know how far I can push. You can feel the potential of your business according to your staff. They are the most important part of the business. I cannot fail with them."

On a Friday night at his formal and discreet restaurant, Les Saveurs, in Mayfair's Curzon Street, some cracks in the Gallic veneer are evident. The wrong first course is brought to one table, while the correct dishes - of trout tartare and a terrine - take at least three quarters of an hour to appear.

"Of course, it is impossible to be there all the time," says Novelli, "but I remember one American woman actually tried to sue The Castle at Taunton a few years back, because Gary Rhodes was not there on the Sunday night she visited".

Anthony Tobin argues that the tension between quality and expansion will always be there for a prestigious chef. "They are generally very poor people and, of course, there comes a time when they want to make money. And if they are fair to people, and if they are good, it will work."

Tobin has decided to stick with his own Reigate kitchen but, at the same time, to help run a chain of Italian restaurants with an entirely different cuisine to his own.

"After all," he explains, "you never see an empty Italian restaurant".

There are still a few purists left though, who, like Tobin's mentor Nico Ladenis, have stuck to their stoves and stayed in the kitchen. Sally Clarke, of Clarke's in Kensington, is one such, although she suggests that it is all really a question of temperament.

"It is a team effort, but at the end of the day it should be down to me to get it right. It is my fault when we win and my fault when we fail."

After 13 years she has learnt to put Clarke's before everything else. "I know some people like Marco Pierre White, or Alastair Little, choose to spread themselves a little thinner. I guess it is just my problem that I want to be here to watch everything," she says.

Perhaps Raymond Blanc should heed his own words: "Chefs today only talk about how many guests they have and how many places they have. It is very dangerous because there have to be some parameters. A restaurant should be about hospitality."