No, I couldn't get even lower. And no, I couldn't look puzzled, let alone 'really puzzled'. It was difficult enough to squat behind the bed of crematorium flowers that had been chosen as the setting for my next piece to camera. But the suggestion that my face should register anything other than acute discomfort in such a position was as ridiculous as the notion that a person of my age was physically capable of sinking into a deep crouch. There comes a point in the making of any television documentary where the original thesis of the programme begins to recede into the middle distance and the technical details take over. In the first few weeks of making this new programme for Channel 4 on contemporary attitudes to death and dying I'd kept a pretty clear idea in my head of how the pictures that were being taken related to the ideas that I wanted to get across. I could see, for example, that the several minutes film of me sitting in a pew at the crematorium would be an ideal opportunity for me to do a voiceover about the amount of time a person of my age had to set aside for burying relatives and old friends. I could also see that the film we'd shot a couple of days before of me standing outside a hospice would be just right for my commentary about how few people would ever see the inside of a hospice when they were dying and how most would instead breathe their last in a solitary bed in a busy NHS hospital ward.

But now, as I surreptitiously attempted to correct the wobble in my squat by burying my right fist into the damp earth of the memorial bed, I realised that once again I'd stopped being the prime mover and become merely a focal point in the director's lens. "You couldn't lie down among the flowers, could you? Flat on your back so that it looks as though you are lying in a flower strewn coffin." I dutifully stretched myself out on top of the carnations. "No, Laurie. I don't like that. It looks absurd. Let's try something else."

Ten minutes later, I'd voluntarily gone back inside the crematorium, climbed up onto the high rostrum where the coffin is displayed during the service, and lain down lengthwise on the rollers which help the bearers slide their burden into place. Then the director's assistant, Robbo, pressed the button on the lectern — "wait for it, wait for it; now" — allowing the mechanism to carry me four feet down into the rostrum's pitch–black interior. It was only when I was halfway down that I realised no one had checked out the interior of this burial pit. Was it just possible that when I reached the bottom I'd hit a conveyor belt which would promptly carry me at high speed into the crematorium ovens? No one in the camera crew would have missed me. Out of shot is out of mind.

"Once again please. And Laurie, this time could you sit up and then just before you sink out of sight wave to the camera. Robbo. Finger on the button. We're filming."

It's just possible that in the end the film will make some of the points that I had in mind when I originally suggested the idea to Channel 4. It might, for example, make the point that although most of us give some thouht to life after our own death, even to such specifics as the tunes we'd like played at our funeral, very few of us ever think about how and when and where we will die. It might help people to recognise that they will nearly all die from a relatively long lasting chronic illness and suffer quite a bit of pain during the process because of the lamentable inadequacies of palliative care in this country. It could even realise its overall aim of getting people to follow the philosopher Montaigne's advice to be "ever booted and spurred, ready to depart".

But I have an ugly sense that a fortnight after it's been transmitted, it will only remain in people's mind because of a single image. "Once again, Laurie. And this time a big smile as you wave. Robbo. Finger on the button. We're filming."

Laurie's film, Last Rights, will be transmitted by Channel 4 at the end of June