A SCULPTED wooden dog stands guard over a rockery studded with quartz, bulging chimney pots and a bonsai collection in Ian and Fiona MacLeod's garden. Fiona is a warm, smiling Scottish woman in her early thirties, but she chain-smokes and her eyes are full of tears.

Ian MacLeod, a former heroin user, was diagnosed HIV-positive in 1984. When Fiona married him three years later, he was unwell and weighed 10 stone. 'Living with someone who's dying is amazing,' she says. 'They wake you up to yourself. They have such a zest for life. They see things you would never notice.'

Support for people with HIV/ Aids has improved - especially in London, where the MacLeods are living. But they can still remember the terrible occasion when a social worker who came to see them ran away when Ian answered the door.

Out of her benefit payments, Fiona cooks wholesome meals with home-made rhubarb crumbles and apple sponges for afters, which have increased Ian's weight to 11 1/2 stone. But every Sunday she has a welcome respite when a white paper bag containing two three-course meals is delivered, free of charge, to their home.

Hazel Ross, a specialist dietitian at St Mary's Hospital, Paddington for patients with HIV/ Aids is adviser to The Food Chain, the only service of its kind in Britain. Every Sunday, volunteers deliver meals to people with symptomatic HIV disease or Aids, and their carers. 'Good nutrition is important because it may help protect the immune system. People with very severe symptoms can lose an enormous amount of weight in a short space of time,' she explains.

Many people with Aids live far away from family and friends. They can become isolated and depressed, and lose the motivation to cook and eat. Some who are too ill to go out avoid Meals on Wheels because of the 'twitching curtain syndrome'. Neighbours can recognise the vans and get suspicious as to why a 25-year-old man can't cook for himself. Food Chain drivers use their own cars to deliver what looks like a take-away. Only first names are used, to protect anonymity.

Apart from a paid administrator, The Food Chain is run by 275 volunteers on a rota basis. All the cooks have had dietary training from Hazel Ross. From two London kitchens, they cater for about 160 people every Sunday and plan to extend to Saturdays.

The service was set up in 1988 by an English vicar who had seen a US organisation - God's Love We Deliver - making Christmas dinners for people with Aids. Originally called after its American counterpart, it later changed its name to The Food Chain. It is not a religious organisation, however, and its volunteers come from all walks of life. With funding from the Government's Aids Support Grant, it provides a service in 25 out of the 32 London boroughs.

Hospitals, GPs, social workers, Aids agencies and health visitors all refer clients to The Food Chain, acknowledging that it plugs an important gap in the care system. Its success has prompted interest from several groups outside London wishing to set up similar services.

Ash is a shy man of 64 with a heart-of-gold face who has been with The Food Chain since the beginning. 'In the old days we'd do the cooking in our own homes and deliver to 15 people. It can be depressing to see the conditions some of them have to live in. I think people who can should do a little over the odds, or the others won't have anything, will they?'

The kitchen, in a community centre in north London, is already a hive of activity at 10.30am. White-hatted cooks sweat over big steamy pots and loud taped music creates a party atmosphere. The chief cook, Kitch, is an accountant in an oil company. He started this morning at 7.30. 'I'm gay and the issue is close to my heart. I prefer to help in a direct way rather than put money in a box.'

Today's menu is oriental salad, roast chicken or aubergine and polenta bake with buttered potatoes and vegetables, followed by apple and banana cake with apricot sauce. All the meals are high in calories and protein, to keep up body weight.

Mike Pennell, one of the founders, is standing like a general flanked by a pile of road maps on which each address is marked by a red arrow. The waiting drivers, complete with dinners, notebooks and maps are dispatched with what Mike calls 'machine gun' precision. My driver, Laurel, is in her twenties and unemployed. She could claim petrol money, but doesn't bother.

The delivery run to seven addresses in west London is sobering. The faces are so young. An Irish man in his dressing gown hovers on the doorstep: 'Did you find the flat all right? I thought you were the district nurse.'

For some clients this is the only contact they have with the outside world all week. One young man who had mentioned to Laurel that his mother was staying that weekend was given a meal for her, too. No one has to experience the loneliness of eating while someone looks on.

Flexibility is all-important. They cater for vegetarian, lactose- and gluten-free diets, they mash up food for people with no teeth, and put faces on the puddings for the 10 children on their books. At Christmas and Easter clients get hampers stuffed with goodies.

The meals - generous, nutritious and beautifully presented - are intended as much as gifts as belly fillers. 'Food is a form of greeting,' says Mike. 'If someone has taken the trouble to cook for you, you know there are people who care.'

The success of The Food Chain raises difficult questions about state provision and the role of voluntary agencies. Because of the stigma still attached to HIV/Aids, many people The Food Chain caters for face being abandoned by society. But why shouldn't other groups - the elderly, the disabled - benefit from services as good as this?

'Society doesn't want to see older people starving to death,' says Mike, 'but in general people are happy to know that there is basic provision for them. We have made people see that the services available just aren't good enough.'

Agencies run by highly motivated volunteers will always be able to outstrip statutory bodies, which could never hope to offer such a flexible and personalised service. Perhaps the answer lies in more state funding for organisations such as The Food Chain to enable them to employ staff and take on a greater workload.

Mike Pennell's dream is to get The Food Chain up and running seven days a week. 'This thing has taken over my life. We do get sad. But there are a lot of brave people out there, and we are pleased to be a part of their lives.'

The Food Chain is at 100 Shepherdess Walk, London N1 7JN (071-250 1391).