These matters have become discussable with one’s friends, not, of course, as a frequent part of gossip over lunch in the dining room (our only communal occasion) but from time to time, perhaps when admiring someone’s stoicism if their frailty is becoming painfully apparent, or feeling sad at someone else’s inability to accept what seems to be imminent. As a result of this openness, I think that most of the people here would consider it foolish to be frightened of being dead. All of us, however, feel some degree of anxiety about the process of dying.

The chief side effect of this pain is numbness in the extremities, filling me with the not irrational fear that I shall lose the ability to write. Without that ability, I feel sure in advance, my “will to live” would be hugely attenuated. I often grandly say that writing is not just my living and my livelihood but my very life, and it’s true. Almost like the threatened loss of my voice, which is currently being alleviated by some temporary injections into my vocal folds, I feel my personality and identity dissolving as I contemplate dead hands and the loss of the transmission belts that connect me to writing and thinking.

It was fear of suffering before dying, and of, you know, lingering on, being in a hospital bed. And I hate hospitals, always have done. I think they're horrible places, even though I spent most of my life working in them. No, it's really - death itself holds no fears for me at all, as far as - I love the famous 18th century philosopher David Hume, who on his deathbed was asked, aren't you terribly worried about what will happen after death? And he said, no, I'm no more worried about not existing after death than I'm worried about not existing before I was born. And that is my view about death. I don't believe in an afterlife. But I know, as a doctor, that dying can be very unpleasant.

I've always felt that death is the greatest invention of life. I'm sure that life evolved without death at first and found that without death, life didn't work very well because it didn't make room for the young. It didn't know how the world was fifty years ago. It didn't know how the world was twenty years ago. It saw it as it is today, without any preconceptions, and dreamed how it could be based on that. We're not satisfied based on the accomplishment of the last thirty years. We're dissatisfied because the current state didn't live up to their ideals. Without death there would be very little progress.

It occurred to me that at one point it was like I had two diseases – one was Alzheimer's and the other was knowing I had Alzheimer's. There were times when I thought I'd have been much happier not knowing, just accepting that I'd lost brain cells and one day they'd probably grow back or whatever. It is better to know, though, and better for it to be known, because it has got people talking, which I rather think was what I had in mind.

Let us consider me as a test case. As I have said, I would like to die peacefully with Thomas Tallis on my iPod before the disease takes me over and I hope that will not be for quite some time to come, because if I knew that I could die at any time I wanted, then suddenly every day would be as precious as a million pounds. If I knew that I could die, I would live. My life, my death, my choice.

I remember what George said and vowed that rather than let Alzheimer's take me, I would take it. I would live my life as ever to the full and die, before the disease mounted its last attack, in my own home, in a chair on the lawn, with a brandy in my hand to wash down whatever modern version of the "Brompton cocktail" some helpful medic could supply. And with Thomas Tallis on my iPod, I would shake hands with Death.

When my father was in his terminal year, I discussed death with him. I recall very clearly his relief that the cancer that was taking him was at least allowing him "all his marbles". Dementia in its varied forms is not like cancer. Dad saw the cancer in his pancreas as an invader. But Alzheimer's is me, unwinding, losing trust in myself, a butt of my own jokes and on bad days capable of playing hunt the slipper by myself and losing. You can't battle it, you can't be a plucky "survivor". It steals you from yourself. And I'm 60; that's supposed to be the new 40.

When Milton's Satan stood in the pit of hell and raged at heaven, he was merely a trifle miffed compared to how I felt on that day. I felt totally alone, with the world receding away from me in every direction, and you could have used my anger to weld steel. Only my family and the fact I had fans in the medical profession, who were able to give me useful advice, got me through that moment.