David Harris was 21 when his car skidded off the road, crashed into a tree and caught fire one icy winter evening. Knocked unconscious by the impact, he suffered horrific burns to his arms, face and neck before passing motorists pulled him out of the wreckage.

Mr Harris was rushed to the nearest hospital where staff fought to keep him alive. Once his condition stabilised he was transferred to a local burns unit where his burnt tissue began to heal.

But two months after his accident, Mr Harris began to take on the appearance, in his own words, of a monster. Red and purple leathery scar tissue up to half an inch thick, known as hypertrophic scarring, began to form on his face, neck and chest. It was dry to the touch and itched terribly. 'I thought, my God, what am I going to look like? What has happened to my life?' he recalls. 'You really start feeling sorry for yourself then, angry and hopeless all at the same time.'

Mr Harris became increasingly disfigured: as the scar tissue contracted, it dragged the right side of his face down towards his chest and pulled his lips apart in a perpetual snarl. Like others who have survived serious burns, he seemed condemned to a life of disfigurement, social isolation and painful plastic surgery.

But Mr Harris and others like him are being helped to face the world again by a plastic mask developed at Queen Mary's University Hospital, London. The mask, which can be worn 24 hours a day, does not interfere with the ability to talk, eat or laugh. By keeping constant pressure on the face it can reduce scarring and transform the patient's appearance.

Hypertrophic scarring is the result of an overgrowth of collagen, the fibrous protein that forms part of the supporting tissues of the body. The body accelerates production of collagen in response to injury caused by severe burns. The burnt skin has lost its elasticity, so that as the scar tissue begins to heal it also begins to contract.

It has been known by doctors for hundreds of years that applying pressure to burnt tissue to restrict the blood supply can reduce hypertrophic scarring. In the 16th century sheets of lead, moulded to the shape of the legs or arms, were used for this purpose, while today strong, elasticated bandages are used.

Heads are more difficult. Elasticated material simply stretches across the concave areas without applying pressure; it is also very hot, extremely uncomfortable and makes the wearer look like a cross between the Phantom of the Opera and a bank robber. Many patients endure bandages on the face for a day or two, before giving up. For children, who make up 40 per cent of burns victims, there is the additional problem that tight, elasticated material can restrict head growth.

Plastic masks have been used to prevent hypertrophic facial scarring since the Second World War, when fighter pilots were badly burnt on the face. But the early plastics were smelly and discoloured rapidly, and doctors could never get patients to wear them for long enough.

More recent versions were also unsatisfactory; to obtain enough even pressure on the face they had to be made in one piece, jamming the patient's jaws inconveniently shut.

Four years ago, Mark Cutler, a cranio-maxillofacial technologist at Queen Mary's, began to tackle the problem. Turning his back bedroom into a laboratory, and working evenings and weekends, he developed a mask made from an inert clear plastic which, unlike the material used for previous masks, does not react to the skin: it is called polyethyleneterethphalate, or PET for short. It has a hinged jaw which is attached using special elastic bands supplied by the hospital's orthodontics department and allows wearers to speak, eat, drink and even laugh, while the necessary pressure is kept on their scars.

Mr Cutler took a plaster of Paris impression of Mr Harris's face so as to produce a custom-made mask. Mr Harris has now worn a mask (or articulated facial splint as it is technically known) 24 hours a day, seven days a week for a year, removing it every two hours during the day for cleaning. Already, the results are remarkable. The terrible scarring has flattened out and lost its livid hues, and his face and lips have regained their normal shape.

'When they sent me home from hospital with the mask, I didn't go out for months, but eventually you have to. You get used to people staring. My close friends are so used to it they say they hardly notice any more,' he says.

He is quite happy to wear the mask for another six months. 'It is actually more comfortable with it on than off. You sweat inside the mask and this keeps the scar tissue moist and flexible and stops it itching. After a few days it was uncomfortable to spend any time without it. I know it's ridiculous, but I'll miss the old mask when it's gone.'

The 'really tough thing' will be returning to his work as a plumber. 'But my face is getting better all the time and I am determined to get back to normal life again.'

Mr Cutler says: 'David will never look the same as before his accident, but the improvement is fantastic.'

Ten years ago, a patient as badly burnt as Mr Harris would almost certainly have died, but emergency medicine has developed to such a degree that it is now possible for people like him to survive. 'When racing driver Niki Lauda crashed and was terribly burnt in 1976, everyone was amazed that he survived,' Mr Cutler points out.

'Treatment has improved to such an extent that patients with worse burns than Niki Lauda's are now surviving - but in what kind of state? These poor, disfigured individuals may be triumphs of medicine but they are tragedies of humanity. With this simple and cheap technique we can improve their quality of life immeasurably.'

John Clarke, a consultant plastic surgeon at Queen Mary's, says: 'These masks are a godsend. Without them, healing takes much longer and the final result is very different. The masks shorten the hospital stay by speeding recovery and will hopefully reduce the amount of reconstructive surgery needed.'

In terms of NHS expenditure, and compared to plastic surgery, Mr Cutler's masks are incredibly cheap: a course of treatment costs a few hundred pounds. The materials cost about pounds 7 and each one takes a day to make. Patients wear their mask for anything up to 18 months and will need between five and 10 updated versions over that period as the scars slowly flatten and the face resumes its normal shape. Children need more versions since their faces are still growing.

Masks have been made for about 30 burns patients at Queen Mary's. The benefits are not only restricted to recent scarring, says Mr Cutler. 'The younger the scarring, the more responsive it is, but the technique works with old-established scars as well; it just takes a bit longer. I have one customer who was burnt 17 years ago and there has been a quite dramatic improvement in his scarring in the months since he started wearing a mask.'

(Photographs omitted)