Imagine a cross between a garden party, mobile menu dégustation, Italian sagra and celebrity cook-out and you get some idea of the flavour of the Taste of London restaurant show, now in its third successful year. If you want to watch Michel Roux cooking saucisson Lyonnais en brioche in the open air, taste Giorgio Locatelli's prawn ravioli and quiz Shane Osborn about the precise ingredients in his pumpkin and ginger soup, this is the event for you. Forty of London's top restaurants and best-known chefs are planning to erect mini-kitchens in the bucolic surroundings of Regent's Park and lay on a spread of taster-size helpings of their signature dishes for your delectation. It's a unique celebration of the London restaurant scene that's as popular with chefs as it is with their customers.

When you've finished sampling the delicious morsels on offer, you can waft through the show, glass of champagne in hand, picking up a wealth of food and drink supplies for your own home cooking. There will also be beer and wine tastings, cookery workshops, and demonstrations. Frankly, it's hard to picture a more civilised way to spend an afternoon or evening in London in June.

2006 sees a London restaurant scene that's more eclectic and robust than ever. Cast an eye down the list of restaurants showing at Taste and you'll find classical French (Le Gavroche), contemporary Indian (Mela), authentic Italian (Al Duca), Thai (Nahm), an inspired combination of all the above (Hush), and everything in between. Modern British (Marcus Wareing, Tom Aikens) makes a strong showing, as does the simplest and best of British ingredients (courtesy of Smiths of Smithfield). With Yauatcha at the fore, the renaissance in Japanese food in general and dim sum in particular is as vibrant as ever; but if you're after classic English summer food (think Dorset crab mayonnaise, as supplied by Inn the Park) you won't be disappointed either.

In fact if you find the sheer breadth of choice on offer on London's streets a little bewildering, Taste is a brilliant way of sampling a particular restaurant or chef without committing to major time and expenditure. If past years are anything to go by, chefs and punters alike enjoy a party atmosphere. This is food as it's meant to be: convivial, relaxed, and taken with just the right degree of seriousness. For the chefs themselves (and they include Jamie Oliver, Antonio Carluccio, John Torode, Alan Yau and Aldo Zilli, alongside many others), Taste is a chance to meet their customers and each other. A chef's schedule being what it is, opportunities to hang out with his or her compadres are few and far between, so when they're not catering en plein air for hundreds, the chefs will be buzzing from stall to stall and swapping gossip.

In short, Taste of London is 'an adventure playground for all those who enjoy eating out', as Fay Maschler puts it. Go, enjoy, and above all, try something new.

Giorgio Locatelli

The chef-owner of London's Michelin-starred Locanda Locatelli is Britain's most famous Italian chef, and probably its most talented, too. But it's as a consultant at Refettorio, a restaurant for excellent, more everyday eating in EC4, that he's appearing at Taste of London.

At Refettorio, the emphasis is on superlative Italian ingredients sourced from the suppliers, so it's only right and proper that Locatelli offers the simple yet delicious toasted bread flavoured with garlic leaves and topped with salamata piacentina ( a kind of cooked pancetta) as a starter. After that he'll be treating us to prawn ravioli with prawn vinaigrette and a fresh fruit mousse. 'The salamata piacentina is probably my favourite out of the three,' says Giorgio. 'It's DOP-marked and comes from Lombardy. I strongly believe in maintaining the link between the producer and what is served on the table.'

'Taste of London is very close to my culture. It's bringing the food to the people and the theory is it will be cheaper than going to a restaurant.'

Where else will he be eating? 'At Nahm. I love their green papaya salad.'

Rainer Becker

German-born Rainer Becker fell in love with Japanese food as executive chef at the Park Hyatt Hotel in Tokyo. He launched his modern Japanese restaurant Zuma in 2002 and it was joined by Roka, which serves Becker's take on grill-cooked robatayaki cuisine, in 2004. Both restaurants have won numerous awards and are separately represented at Taste.

'For Zuma we're going to do crispy fried squid with green chilli salt,' says Becker. 'People love it, even if they don't like squid. Because it's such a huge audience we're not doing anything too complicated or spicy. Alongside the squid we've got sesame seared salmon and barley miso marinated chicken legs; miso is made of fermented soybean paste and is actually very healthy.

All the dishes have a barbecue feel to them and are easy to eat.' Roka will be serving scallops, lamb cutlets, and strawberry and jasmine ice cream. 'All the great food cultures are now represented in London and this show is a celebration of that. Of course it's also a marketing thing; lots of the visitors won't know my restaurants. And it's fun for all the chefs. We work so hard we don't get to see each other very much.'

Angela Hartnett

The Connaught's head chef is, remarkably, the only woman cooking at Taste, which says something about the extraordinary dominance of the male chef on the London scene. Not that Hartnett can't hold her own. It was mentor Gordon Ramsay who put her in charge of operations at his restaurant in the Dubai Hilton before moving her back to the Connaught in London, where she subsequently won a Michelin star. Harnett's cooking brilliantly blends Italian, French and modern British, reflected in her choice of dishes.

'My favourite is the vanilla mille feuille with roasted peaches,' she says. 'I love puff pastry and it's the kind of thing you can eat in your fingers. For the starter, a pressed tomato mosaic with olive tapenade, I was really inspired by seasonality. It's also got aubergine and courgette, which are summer vegetables.' The Italian theme continues with her king prawn tortellini, fennel purée and herb vinaigrette.

This will be Angela's first year at the show. 'Gordon said it was great fun,' she says, 'and I'm looking forward to trying all the other stalls. I definitely get inspiration from other people's cooking. It sparks my imagination.'

Tom Aikens

Fiery wunderkind Tom Aikens, 35, has a reputation for technical brilliance and a lavish generosity with flavours. In 1996, while cooking at Pied à Terre, he became the youngest British chef to be awarded two Michelin stars, and his eponymous restaurant now has its own Michelin star.

For Taste of London he's managed to translate his talent for complexity and flair into dishes which, as he puts it, 'are easy to put together. After all, we will be cooking for hundreds of people'.

His braised pork belly with chickpeas and paprika squid is followed by beef shin braised in Guinness with pommes purée and roasted parsnips and an updated rice pudding - mango rice with mango parfait and mango mousse. It's just the kind of hearty, warming food we might be glad of as the English summer evening draws in.

This is Aikens first time at Taste: 'Everybody seems to be doing it this year. It's great publicity for us. I'm going to be the one cooking on the stall so I don't know if I'll get time to try anything else. But I'll be interested to see what Le Gavroche comes up with. And I love Thai.'

Cass Titcombe

Cass Titcombe's modern British all-day restaurant Canteen, launched with business partners Dominic Lake and Patrick Clayton-Malone, is all about quality ingredients, locally and seasonally sourced, prepared according to neglected British recipes and democratically priced. It has enjoyed huge success since opening in November 2005 and Titcombe's Taste choices are absolutely in character: potted duck and piccalilli; fish and chips; and blackcurrant jelly and ice cream. His favourite, he says, is the pudding, inspired by memories of his father, whose job it was to visit fruit farms to 'quality control' the blackcurrants before they were picked. 'Plus, school dinners and being desperate to eat things like jelly and ice cream as a kid.'

'Fay Maschler suggested us to the organisers and it was great to be asked to be part of it because the quality of participants is so high. It's also an opportunity for Canteen to show off the delights of great British food.' What other dishes is he aiming to taste? 'I am looking to visit Fino and taste theircrisp pork belly. I'm also going to get hold of some authentic Thai from Nahm and anything from Umu; I love good Japanese.'

Shane Osborn

Shane Osborn's disarmingly laidback Oz style can't disguise his impressive talents. His two Michelin-starred restaurant Pied à Terre, now reopened after the fire of 2004, is adored by knowledgeable gourmands for a menu which blends complex flavours and sophisticated techniques with Osborn's native warmth and lack of pretension. 'For Taste of London we're preparing chilled pumpkin and ginger soup; it's very simple but the flavour blows people away and lingers in the mouth. I discovered the recipe as a hot soup when I was training in Australia, but it's better cold. We put toasted pumpkin seeds and crystalised ginger on top so you get the textures as well as the flavour. After that we're doing peppered seared tuna and basil-scented pannacotta. We're not trying to show off, just provide some interesting flavours.'

Osborn is looking forward to trying some 'fresh tandoori' and checking out what Jun Tanaka of Pearl restaurant is up to. 'There was a really good atmosphere last year; all the chefs got on very well together. And I like conversing with the customers. I'm always listening to what they have to say about my food.'

Michel Roux Jr

In 1967, the year Michel Roux Jr's father Albert opened Le Gavroche in Sloane Street, it was impossible to get proper French cooking in the capital. Since then the Roux dynasty has worked wonders on the British palate, and nearly 40 years on, Le Gavroche is a beloved London institution.

Michel is a firm believer in cuisine du terroir, cooking of the regions, and for Taste of London is preparing a fabulously satisfying-sounding saucisson Lyonnais en brioche (think superior sausage sandwich). 'I worked with Alain Chapel in that region and he was a big influence on me,' says Roux. 'It's the kind of food you can do very simply at home for friends and eat with a good bottle of Beaujolais. I love charcuterie and offal - we served braised ox cheeks in red wine in the restaurant the other day and people loved them.

'I'm planning to taste everything at the show. I'm particularly keen on Zuma's deep-fried squid and Mourad's tagine from Momo.' And the London restaurant scene? 'It's going from strength to strength but the show really helps.'

· To reserve your place at Taste of London: visit www.tasteoflondon.co.uk, or call the booking hotline 0870 128 3622