We all have fantasies of how we'd like to die. A soft trickle of Mozart, a haze of distant hills, a circle of closest friends and family around you. That, I guess, would do for most of us.

We also have firm feelings about how not to die. For myself, I would rather not die as my father recently did.

My dad was 96 and - when the time came - was unsentimental to a fault. He'd had a good innings, he didn't want to waste anyone's time. To the kindly doctors and nurses assembled around his bed he spoke warmly but firmly. "You've got much more important priorities than keeping me going," he told them. He chose the euphemisms of his generation, but his meaning was clear: he wanted them to end it for him.

I felt obliged to intervene on the doctors' behalf. "I'm not sure they can do that, Daddy," I told him. The doctors smiled knowingly and nodded agreement. My father grew irritable at their failure to understand. I did my best to argue on the side of medical reason.

But, actually, I think my dad was right. The coming days, our last precious time together, were clouded by his growing pain and sense of betrayal - he blamed me and my brother for our failure to persuade the doctors to carry out his wishes. Instead of tranquillity there was bitterness and bewilderment.

"They wouldn't treat an animal like this," he groaned each time the ulcers in his leg threw his whole body into spasm. He was right about that, too.

It was not quite the script the consultant had gently outlined just over two weeks before my father eventually died. He had set out the options: amputation of his remaining leg or letting nature take its course. "Nature" meant anything from severe ulceration to gangrene as the circulation in his "good" leg packed up. It could be days, or it could be weeks. We were not to worry: they could control the pain.

My father was quite clear he couldn't face another amputation. So it was simply a matter of nursing him to a quiet, dignified - and painless - end.

But they were wrong about the pain. My father was, so far as we could tell, quite often in agony. And my brother and I were placed in the awkward situation of begging, cajoling and - in the end - demanding that he be given ever higher doses of morphine.

Different members of the medical team appeared to have different views about what was an adequate or appropriate dose. The night team countermanded the day team. The palliative care team didn't work weekends. At one point my father weakly changed his mind. He couldn't take this pain any more: perhaps he should go ahead with the amputation. But, of course, by now he was too frail for an operation. This logic drove him into furious exasperation.

I had a tense conversation with one Macmillan nurse to whom I had suggested raising the dose of morphine. "We have ethical and legal difficulties with sedation," she sniffed.

"I'm not asking you to sedate him," I replied. "I'm asking you to do what he was promised - to be allowed to die without pain."

"But if we gave him a higher dose he would fall into unconsciousness," she said. "And then we couldn't tell if he was in discomfort or not."

Eventually he did fall into a deep sleep and we asked that the medical team remove the drip which could have only prolonged it. A nurse explained that, effectively, he would die of dehydration. There would come a point when his internal organs would pack up.

My brother and I visited every day, spending hours by his bedside. But, as luck would have it, the dehydration finally took its course at a time when neither of us was there. So my dad died alone.

I assume everyone involved in my father's last few days behaved as they had to. But I would defy anyone to call his ending a "good" death, or even a particularly ethical one. Why is withholding nourishment and treatment as an old man withers away from dehydration more ethical than intervening to help him die at the time and in the manner of his choosing?

Were I ever to be faced with the same situation, I would like to have an option denied to my father. I would like to choose, well, Beethoven actually, then bid farewell to friends and family and ask that I might gently drift away under a general anaesthetic, followed by whatever would stop my heart as swiftly as possible.

It seems - from the current debate within the medical profession - that a good many doctors would be willing to help, if only they could do so without fear of prosecution. Isn't it time we let them?