Supermarket shelves are groaning under the weight of Antony Worrall Thompson. That's not a slur on the television chef's size or shape, but a nod to the success of his commercial empire. His new range of ready meals will extend to well over 100 the number of products made under licence and bearing his name. Worrall Thompson's beaming face can be found on everything from gravies and breadsticks to herbs and spices and ranges of kitchen and barbecue equipment. The brand is now worth more than £60m [Mintel].

Elsewhere in the supermarket, Jamie Oliver's 40-strong premium food range, comprising pasta sauces, herbs and oils, offers wannabe cooks who identify with the chef's cheeky persona a chance to imitate his cooking. Hundreds more products bear the names of various Michelin-starred glitterati.

So how closely are the chefs involved in these ranges? There's clearly a lot of money to be made, with a cut of the takings and bonuses for appearance fees (though the exact financial arrangements are more closely guarded than the recipes themselves). But a debate is raging in restaurant kitchens nationwide, sparked by superchef Marco Pierre White. At its heart is the integrity of celebrity chefs making fortunes on the promis e that their products - and indeed the recipes in their cookery books - match the dishes they serve up in their restaurants.

"I'm not pretending I'm the creator of these soups," Pierre White said of his range of soups that sell for £1.99 a pot in Morrisons. "Anyone believing that I am is a fool. I cook Michelin-starred food - that's my talent."

By coming clean about his lack of involvement in these products, Pierre White appeared to be attacking fellow chefs who choose to be less upfront. It's a big issue, according to TV chef Phil Vickery, who says the priorities of too many chefs in recent times have swung from cooking in the kitchen to getting a product endorsement, a book deal or a television show. "I was cooking for 17 years before I appeared on television," says Vickery. "When I write my books, I fill them with dishes that I cook. Anything else is cheating."

Vickery says several well-known chefs have no connection to what is written in their books or the recipes that make up their products. "Their restaurant businesses are often completely underpinned by their product ranges and television shows. A TV show is part of a chef's commercial business and will then drive a book deal - it's hard to get a book deal without it. But some are forgetting what made them big in the first place and that's cooking good food."

Vickery took nine months to hone the recipe for his first two products - Christmas puddings to be sold under the Seriously Good Food brand. He points to other chefs who are doing things "the right way" such as "the passionate" Hugh Fearnley Whittingstall and the "fantastic" Rick Stein. But he fears the estimated 14 million consumers who buy celebrity-endorsed food products are at risk of being "conned" by others who take no interest in the products and recipes carrying their names.

With the celebrity-branded food market still growing and ample opportunity to develop into markets such as organic and Fairtrade , Rune Gustafson, chief executive of branding consultancy Interbrand says chefs must retain credibility if manufacturers are to continue using personalities to sell products.

"Consumers must feel the celebrities are staking their reputations on the product," he says.

One celebrity who seems to have taken this to heart, from the launch of his first range in 1995, is Loyd Grossman. Though not a chef, Grossman is a self-confessed food obsessive and is sufficiently well respected for his knowledge to be seen as the godfather of celebrity-branded food in the UK retail market.

"Our brand philosophy is simple," he told The Grocer. "If we feel we can do it better than anyone else we'll go for it. It's driven by a love of food and an enormous respect for the customer. Customers can't be fooled."

The formula is working. At the end of 2007, Loyd Grossman sauces, made by Premier Foods, were the third-largest pasta sauce brand after Dolmio and Ragu and worth £50m. The television presenter also has a range of exotic breads and Italian biscuits made by Rivermill Foods and a pasta range produced by Pastificio Lucio Garofalo. In August 2007, Sun Valley launched a Loyd Grossman range of nut mixes expected to generate sales of £1.8m in its first year and this February Grossman teamed up with Quorn to produce Quorn pieces marinated in Loyd Grossman sauces, using the Loyd Grossman brand to drive further recognition of Quorn as a mainstream meat-free brand.

While there is clearly a right and a wrong way to endorse food products as a chef, making them under licence for celebrities can also present a learning curve for the manufacturers. Grossman is the only person outside of Premier Foods who has any say over any part of its portfolio. Sue Knight, Premier Foods' director of culinary brands, says the company relishes its exclusive relationship with Grossman but acknowledges it takes a special personality to work on the brand team. "At Premier we have a fast-moving, pragmatic and aggressive culture. But to work on the Loyd Grossman team, you need to be able to balance that culture with a softer, more emotional and less aggressive side."

Knight admits that, at times, Premier has felt the need to temper Grossman's creative vision .

" Now and again we've had to persuade him that his idea may not work - he wanted to launch a wine and he was interested in producing an oil.

"Don't get me wrong, Loyd has a good head for business and a vested interest in the size and performance of the brand, but when we report to him we do it not only in business terms but in emotional terms as well," she adds.

Times change, though, and old rejected ideas may yet see the light of day. "When Loyd approached us years ago to make sauces for him, that was well within our capability. With every new acquisition this company makes, that capability to try new things grows with it."

For his part, Grossman says when he launches his next product it will, as usual, be based on instinct. "I'm not calculated enough to avoid categories where there is already a degree of saturation. There are some places I know I won't go. I'm not about to launch into crisps, for example. "

And it won't be just for the money, although Grossman says he is happy with the "business arrangements" he has with various food companies.

But why is Grossman's brand so successful - is it because his face is on the jar or because of the product's quality? The former Masterchef man believes it is a combination of both factors. "It only works if both parties work in the same way and share the same values. I've never been into the 'take the money and run' approach. I need to feel that the food manufacturer I'm working with has the same passion for the product as me."

Knight agrees. It is, she says, Grossman's "extraordinary knowledge and palate" that drives the success of the brand. " He'll send a sauce back to our chefs five times if he doesn't think the basil pieces are the right size."

Celebrity chefs interested only in the next way to cook up a pile of cash should take note.nDo celeb chefs teach us to cook better?

38% of population has prepared recipe from celebrity chef cookbook/TV show

34% of population has bought celebrity-chef-branded food

10% of population has eaten in a celebrity-chef-owned

restaurant

75% of 'modern mums' believe TV dishes are 'impossible' to recreate at home

66% of 'modern mums' claim to feel inadequate when attempts to cook celeb chef dishes fail

Sources:

Mintel, Quality Standard Markchefs: who sells what?

Antony Worrall Thompson retail sales value £60m



With more than 60 lines, AWT works with several manufacturers to licence products from kitchen and BBQ equipment to herbs, spices, seasonings and sauces. His latest foray is into the ready meals market, with soups soon to follow, in a tie-up with 2 Sisters.

Loyd Grossman retail sales value £60m



Launched in 1995, the brand builds on the man as a foodie icon. Grossman is involved in every aspect of product development, from sourcing of ingredients to packaging. "If our ideas coincide," he says of his relationship with manufacturer Premier, "then we go for it."

Gordon Ramsay retail sales value £8

m

Launched in 2002 and manufactured by Ashbury Confectionery, Ramsay's chocolates were worth £8m in sales at the last count. In December 2006 he said he wasn't worried about the standard of the chocolates because they were £3.99. They retailed at £5.99.

Jamie Oliver retail sales value £7.5m



The Jamie Oliver range was ramped up in March , with 40 new food lines including pasta and pesto sauces, herbs, oils, antipasti and bagged salads added to a predominantly non-food line up, as Oliver's joint venture aims to more than double sales to £16m by 2010.

Jean-Christophe Novelli retail sales value £2.1m



In December 2006, Novelli launched a range of frozen ready meals in partnership with Findus. The products bear the tagline: "Restaurant-quality food you can enjoy every day." The range includes lasagne, lemon & honey chicken, Mediterranean rigatoni and crêpe crumble.

Ainsley Harriott retail sales value £2m



The Ainsley Harriott food brand is centred around Harriott's charismatic, larger-than-life persona, with the aim of making cooking fun and easy. The range include marinades, barbecue sauces, dressings, risotto, cous cous, soups and stuffings. Works with several companies.