A teenage boy in chef's whites leads the way up the stairs and through winding school corridors. Opening the door to allow his guests in, he offers to hang up coats and bags before pointing towards the beautifully laid-out table. Juice is poured into glasses and bread rolls are proffered from a basket. The Wandle Valley school bistro is open for business.

Every Thursday, a food technology classroom in this school in Sutton, Surrey, is transformed into a smart restaurant, able to seat up to 15 people for three-course meals. Today, bathed in the sunlight that streams through the large windows, the room looks sparkling and spacious.

The ovens and kitchen worktops sit next to the table, so guests can see the food being produced by the chef and the pupils. At any busy secondary school this bistro would be remarkable, but it is particularly impressive for a school that teaches children with social, emotional and behavioural difficulties.

Before Jamie Oliver

The headteacher, Doug Bone, thinks the bistro has worked wonders for pupils' confidence and feeling of self-worth. "You can see just how proud they are to be working here," he says, nodding at the three boys eagerly helping the chef to prepare the starter. "The bistro gives them the chance to develop as individuals and gives them skills they can go on to use at home. We trust them a lot here and they appreciate that feeling of responsibility. It works. And we realised that a long time before Jamie Oliver did."

Last month, Oliver launched his latest Fifteen restaurant in Cornwall, one of Britain's poorest counties. He opened his first restaurant in east London four years ago, aiming to give disadvantaged young people the opportunity of a career.

Wandle Valley's bistro was opened six years ago and is open to the public for three-course meals every Thursday during term-time. Part-time food technology teacher Doug Kerr and his students have cooked for the local MP, the mayor of Sutton, school governors and local business leaders. It is a world away from what many people expect from an EBD (emotional and behavioural difficulties) school. Wandle Valley provides support to mainstream schools by taking on students who have been excluded or are having problems fitting into classes. There are currently 80 pupils on the roll, only three of whom are girls, and although its GCSE results are not as high as other schools in the area, there is a 100% pass rate.

Bone believes the bistro has a major part to play in changing the attitudes of the local community towards this type of school. "We have invited the chairmen of local businesses in for lunch to talk about work experience and this has had fantastic results," Bone says. Pupils have gone on to enjoy work placements in areas as diverse as retail, childcare and plumbing, partly thanks to the success of the bistro.

Our 15-year-old waiter, Kevin Callus, presents the first course with a smile and a warning that the plate is hot. He is clearly enjoying himself. The starter is a steaming crème champignon - mushrooms in a cream sauce served in a ring of pilau rice. Two boys in the kitchen, both in chef's whites with tall hats, help Kerr to prepare the next course while the visitors tuck in.

The chair of governors, Diana Stern, leans across the table. "Working in this kitchen gives the pupils so much confidence," she says. "When the boys walk around school with their chef's whites on, they seem to be a little bit taller."

Presentation is only one aspect of the students that changes when they start working in the bistro. For some, learning to cook is the biggest achievement in their lives to date. "As an EBD school, we are continually trying to push against the negative image that many people may have of us. But this bistro is showing what the students are really like," Stern says.

There is certainly no messing around in Kerr's classes. His is the most sought- after course in the school, and students don't dare squander the opportunity. Shunning the national curriculum's GCSE food technology route, Kerr has written his own 10-week course, accredited by exam board AQA, which teaches children how to cook food from scratch rather than draw posters about it. For their final project, pupils have to cook a three-course meal in two hours. "What I want to do," he says, "is to teach young people how to cook. This is a course that is based on skill, not research."

Kerr, known simply as "chef" by the students, believes his way of teaching will help students to live healthier lives in the future. Learning to cook properly, rather than relying on ready meals, makes children aware of what they are eating, he says. Not every dish served in the bistro is low in calories (sautéed potatoes, fried fish and scrumptious desserts all feature in Kerr's recipes), but pupils learn that moderation is a good thing.

Fizzy drinks and chips

Anything that inspires children to learn about healthy eating will be encouraged by the government, which has recently published new guidelines on school dinners.

All pupils must now have at least two portions of fruit and vegetables with every meal, and fizzy drinks, chocolate and crisps are to be banned from the autumn. Kevin, who is now serving coffee after a mouth-watering main course of chicken en croute and a dessert of strawberry cheesecake, certainly does not think much of junk food. "I couldn't cook when I first started at school but I have learned so much now. I cooked a lovely meal for my mum on Mother's Day," he says.

Bone groans and pats his stomach as the plates are finally cleared away. He is due to play five-a-side football in a couple of hours and doesn't fancy his chances. "Do you want any more pudding, sir?" Kevin asks cheekily.

Walking out of the school entrance, Bone says: "It's all about trust. The pupils will only learn if they are given the chance to do things. Working in the bistro gives these children an element of responsibility that they may never have had before."

· Wandle Valley school bistro is open every Thursday during term-time from 1pm to 2pm. Meals cost between £5 and £10. Phone 020-8648 1365 to book