Now eat your greens

He apologises profusely for delaying our interview as he shows them Acorn House's recycled plastic chairs, the organic fruit and vegetables on display, the hydrocarbon fridges that use 25 per cent of the energy of a normal fridge and the roof garden above his bin store where he grows corn, lettuce, tomatoes and comfrey.

There is a further delay while he rescues a couple of worms which have escaped from the wormery where he recycles his menus and any paper packaging that his suppliers have been thoughtless enough to send him.

He doesn't look like the man poised to launch a mini-empire aimed at revolutionising the restaurant industry's ethics. But that's what he is. Water House, the second in his planned chain of five restaurants, opens next month.

"It's been mad this week," says Potts Dawson when we finally sit down over a glass of purified tap water. "We've had French TV crews, Japanese style magazines, some Germans, and [members of] the Swedish government in this week to have a look at us."

One year after opening, Acorn House is a success, morally and financially. Situated in the ground floor of the Terrence Higgins Trust's London headquarters, it was originally conceived as a staff canteen for the charity's workers. Potts Dawson, however, had bigger plans.

Having trained from the age of 16 under Rowley Leigh at Kensington Place and with the Roux Brothers, he had gone on to become head chef at the River Café, to launch Ronnie Wood's Harrington Club, and to open three restaurants in Spain. Prior to setting up his own restaurant consultancy, Bliss, in 2005, he was executive head chef at Jamie Oliver's Fifteen, where underachievers receive training in the culinary arts.

When the idea of Acorn House was first mooted, Potts Dawson approached another charity, the Shoreditch Trust, with what he calls "a bigger package".

Acorn House would, indeed, offer staff at the trust lunch for £5. Moreover, everything in it, from the ingredients to the fittings to the wall paint would be from sustainable sources and eco-friendly. And every year he would offer 10 under-privileged Hackney youths a place on a three-year training programme.

Acorn House went down well with food critics. He describes his style as "modern London" which translates into dishes such as roast pork belly with apple chutney, and spiced flourless chocolate cake with ginger ice-cream. The Evening Standard's Fay Maschler has twice picked the restaurant as her favourite of the year.

Design buffs have also found its clean lines and canteen feel appealing, meaning Potts Dawson finds himself both "an accidental expert" on all things green, and accidentally fashionable.

"But I don't do this to be trendy," he snorts. "I do it to make a difference. The restaurant industry is the perfect place to start thinking about saving the planet, because we consume everything: food, energy, paper, cleaning chemicals ..."

At Water House, situated in a building in Hoxton, overlooking the canal and fortuitously owned by the Shoreditch Trust, Potts Dawson is pushing himself even further in reducing the business's carbon footprint.

He has sourced some form of ventilation system which works off the ambient temperature of the canal and which is more energy-efficient than air-conditioning. The kitchen will feature an electric range, fed by hydroelectric power from Scotland. "And I'm seeing if we can get away without using paper, because even if you recycle it, it takes energy," he says. "So we're looking at chalkboards for the menus, and Japanese loos that'll give you a rinse and spray dry."

He must see my sceptical expression. "Well, I'll put a toilet roll in there, so people have a choice, but I might have 'GUILTY' stamped on each sheet. It's about getting people thinking.

"There was never that much money around when I was growing up," says Potts Dawson. "We learned to turn lights off, put a jumper on instead of the heating, and the food was all healthy brown rice, aduki beans, miso paste, lentils ... although as a kid all I wanted was a f***ing Mars Bar, of course. It was thrift rather than eco-thinking, but the result was the same."

He spent holidays on a Dorset farm with his father, artist Rufus Potts Dawson, learning at first-hand the seasonal nature of food and "watching goats get killed", which taught him respect for the (occasional) meat on his plate.

His mother, model Kari-Ann Moller later married musician Chris Jagger, Mick's brother. As one of five boys racketing around the big, draughty house in Highgate, he learned to cook out of necessity. Through his stepfather's work with the Tibet Foundation he also gained an interest in Eastern philosophy.

"Being a vegetarian Buddhist would be a bit harsh to deal with in the kitchen, so I'm a Taoist, I study martial arts, and I don't drink or smoke," he says. "My plan is to open five restaurants based on the five elements in Chinese philosophy: wood, water, fire, earth and metal."

He is a sensitive soul, Arthur Potts Dawson. I can see how he persuaded the Shoreditch Trust to back him.

He says he's earning less now than he was at the River Café. He and his partner of five years, Paloma, a reflexologist, share a rented flat in Highgate with their two children Aron, four, and Tuula, one, and Paloma's two sisters. He says he'll only serve food at Acorn House that he'd feel happy giving his kids. And his attitude to his young trainees is informed by problems his stepbrother John had with crack and heroin.

"My brother's done a great job, cleaning himself up," says Potts Dawson. "But I know from his experience how difficult those sorts of drugs can be to kick. And they are problems in restaurant kitchens now. If I smell dope on one of my trainees I will try and help. I've spent my own money paying for craniosacral treatments [a form of drug therapy] and counselling for some."

Water House is to open on 11 February after problems sorting out that ethical heating system. Doesn't he sometimes envy those of his contemporaries who went for the fame and the cash, and don't worry about sourcing recyclable microfibre table tops? "I just want to serve food that people want to eat, and show a way forward for the restaurant industry, for all industries," he says. "One day, everything I've done will be worthwhile."

Acorn House, 69 Swinton Street, WC1 (020 7812 1842). Water House, 10 Orsman Road, N1 (020 7033 0123).