Euthanasia is tolerated in the Netherlands, but a film that shows Dr Wi lfred van Coyjen killing a patient provoked furious argument when it was shown on Dutch TV. Now the BBC plans to screen it next month. Alix Sharkey reports
The patient is lying on his cot in the living room. He is too sick to get up the stairs. He cannot breathe properly. The doctor leans over and speaks softly into his ear: "Do you really want to die?" Slowly, almost imperceptibly, the patient nods his head.

There is nothing left to him now but a slow and lingering torture, and fading memories of another life. He is weary of this existence. He has set himself for extinction and will embrace it, in order to preserve his dignity. "What can I offer that man?" asks the doctor, Wilfred van Oyjen. "What can I give him? You could give him drugs, but in the end it's only a stop-gap. There's no use. He's going to die and he knows it."

Cees, the patient, used to run a restaurant in Amsterdam with his wife, Antoinette. Then he developed amyotrophic lateral sclerosis (ALS), an incurable, degenerative wasting of the muscles, also known as Lou Gehrig's disease. The illness progressed gradually at first, but suddenly overwhelmed him. His feet and legs became paralysed. The disease spread up his body, immobilising his right shoulder and arm, then spread to his face, partially paralysing his jaw and tongue, so that he could no longer speak properly.

Eventually, Cees was confronted with the full horror of his predicament: his mind, though fully conscious, was trapped in a dying body. He felt like he was being buried alive. Unless he acted first, he faced an excruciating death by suffocation, as the wasted muscles of his chest finally collapsed, and his lungs stopped working.

Cees asks Dr van Oyjen to kill him. Not once or twice, but again and again. The doctor must be convinced. There can be no room for whim or petulance in their mutual decision.

He growls at the doctor, his speech unintelligible to all except Antoinette, his constant companion and nurse. "He says we musn't wait any longer," says Antoinette. Cees make the noise again, a guttural slur. Then he hangs his head and sobs like a littleboy, his numb shoulders shuddering with emotion.

The doctor is reluctant to kill a man, no matter how extreme his condition, but knows what he must do. "I've been asked," he says, "and I feel I must honour that request. If I don't, I'm letting my patient down."

Seated at the dining table in his roomy, open-plan house in the quiet Amsterdam suburb of Duivendrecht, Dr Wilfred van Oyjen looks every bit the middle-class family doctor: tall, greying, mid-forties, unfussily elegant, with a slightly detached air. He has a wife and two teenage children; his home is a testament to lasting values: Mozart on the CD player, Engels on the bookshelf, oil paintings and an upright piano in the corner.

But Dr van Oyjen is now famous for his more radical opinions, thanks to the documentary film Death On Request, which follows the last few months in the life of Cees van Wendel de Joode, up to the point where Dr van Oyjen, his GP, administers a lethal injection and consoles his wife. The film was screened in the Netherlands last October and is to be shown in Britain by the BBC next month .

Death On Request caused a sensation in the Netherlands and prompted TV companies from all over the world to call Ikon, the Dutch production company, asking to buy the rights to the film. Most were only interested in the last five minutes, featuring the death scene. Despite huge offers, particularly from American networks, Ikon refused to sell unless the film was screened in full; the BBC willingly agreed to this condition.

Since the screening, Dr van Oyjen says he has received more than 200 letters from people supporting his actions, many expressing the wish that he were their doctor. "A lot said they had a bad experience with the death of a relative. About 90 per cent were of that kind, where they felt euthanasia would have been a better course." But while the reaction of Dutch religious groups was broadly sympathetic, a spokesman for the Roman Catholic church described Death On Request as "a brutal provocation to those who believe that life is not something that man can decide about".

Dr van Oyjen admits that euthanasia nags at his conscience, but, like many other Dutch GPs, he will overcome his personal misgivings to administer the means of death to a terminally ill patient, provided the official guidelines are followed scrupulously.

These guidelines state that two doctors must diagnose "unbearable" physical or mental suffering, coupled with a voluntary, well-considered and lasting desire to die. There must be no other solution acceptable to the patient; the time and manner of death must not cause unnecessary suffering to others (eg, next of kin); and a medical doctor must prescribe and administer the correct drugs.

There is also a compulsory reporting procedure, whereby the doctor involved must report the death immediately to the local police coroner, who will then check with the second doctor that the proper procedure was followed. This is crucial, because although euthanasia has been tolerated in the Netherlands for the last 10 years, it remains illegal.

Doctors who adhere strictly to the code of practice can expect not to be prosecuted, but every so often the chains are rattled, as they were last year when the Ministry of Justice prosecuted Dr Boudewijn Chabot for giving a lethal drug to an otherwise healthy woman who had decided, following the death of both her sons, that she no longer wanted to live. Though found guilty by the Supreme Court, Dr Chabot was not punished and was allowed to continue practising. But the verdict was a clear reminder that, theoretically at least, doctors who administer means of death face a maximum jail sentence of 12 years, while those who assist a patient's suicide can go to prison for three years.

Dr van Oyjen never wanted to be a physician. His original intention was to become a psychiatrist, but after he left medical school his father, a GP in Amsterdam's Jewish quarter, became ill. So the young Dr van Oyjen took over the practice and, to his surprise, found that he liked it. That was 17 years ago. Now, despite having 3,000 patients to look after (he has a part-time assistant), he says it is "a very good job, a very happy job".

But his mood plummets whenever he is asked to perform another euthanasia. As I arrive, he is on the phone, arranging to get a second opinion on the mental stability of a young man who has been referred to him by the NVVE, the Dutch Voluntary Euthanasia Society. This man, called Ron, is suffering from a condition similar to that which afflicted Cees.

"He is 32 years old, and his only hope of survival rests with a lung transplant," says Dr van Oyjen, staring fixedly out the window at his garden. "He is already paralysed from the waist down. His specialist has told him he must have the transplant eventually, maybe in a year. But he is telling me he doesn't want to wait. He considers this intolerable suffering and says that even if his lungs were working, his paralysis will get worse. His lungs might collapse before the donor organs become available, and that would mean an iron lung. He doesn't want to live that way." Dr van Oyjen now has the unenviable task of ascertaining Ron's state of mind.

What constitutes "intolerable" suffering? Can one make a "rational" decision to end one's own life? Who has the moral right to make these judgements, and administer the means of death? Dr van Oyjen, an ordinary GP, must grapple with these questions regularly. He estimates that he has performed euthanasia "about three or four times a year'' since he took over his father's practice. Understandably, perhaps, he has never kept count.

"It demands a lot of me, it's true. The quality of my life is good, the money, the house and so on. But after a euthanasia, or even after considering questions like this, I come home in the evening and I don't feel very pretty, of course. I can't laugh and joke. It's not possible. When I'm on my holidays it takes me a week before I can get into another rhythm. Even as I speak to you, I'm thinking about this boy, it's nagging me all the time. I see his face, even when I am dancing with my wife."

Once the decision to perform euthanasia has been taken, Dr van Oyjen's prime objective is to ensure "a good death".

As is clear from Death On Request, his main concern is for the feelings of the patient and those present, and he will spend hours, days if necessary, waiting for the right moment to present itself.

"I want to be very close to them,'' he says, "I think it's the only way." Sadly, it isn't. Some viewers complained about Death On Request, saying that it made euthanasia look "too beautiful". Despite the guidelines, Dr van Oyjen has heard some tragic stories, like that of the reluctant doctor who arrived hours late for this critical appointment, then sent the family out of the room while the lethal injection was administered. "Then he emerged and said, `OK, your father is dead'. That is not the right way. That is not a good death."

Almost as bad, he says, is the practice (allegedly carried out on occasion in Britain, where euthanasia can be prosecuted as murder) of steadily increasing the dosage of an opiate such as morphine to a fatal level. Since this can be explained as palliative care leading to "natural" death, there is very little risk of prosecution. "But this can take several weeks, and is dishonest," says Dr van Oyjen. "It also means the patient dies in delirium.

"I am giving people the possibility to make choices. What kind of quality of life, and death, do they want? I have seen a lot of people dying. Death is not always awful. With a good doctor, death can be faithful, like a good friend."