Last Night's TV - Terry Pratchett: Choosing to Die, BBC2; The Walton Sextuplets: Moving On, ITV1

Harsh reality for the fantasy man

Who owns your life?" asked Terry Pratchett, the 63-year-old novelist diagnosed with Alzheimer's three years ago. The question lay at the heart of his profoundly affecting journey to Dignitas to explore the prospect of assisted suicide for himself, and accompany two British men who ended their lives in the Swiss euthanasia clinic.

The media controversy that had swirled around one of these deaths, captured on screen and observed by Pratchett, had threatened to hijack the finer points of this stunning, sensitive documentary. In the end, while Peter Smedley's final moments were highly discomforting viewing, they did not feel like gratuitous or voyeuristic television-making. They hit home the point that had hitherto remained theoretical: that this final cup of tea, this surreal composure, this fast gulping of a poison liquid and this gasping for breath and pleading for water is what it meant to give a man the right to die.

It was wise of the BBC to schedule a Newsnight debate straight after its airing. Pratchett's authored documentary could not have failed to leave a single viewer unmoved or unprovoked, and not just because of the death of Mr Smedley, a wealthy 71-year-old with motor neurone disease flanked by his wife and a Dignitas "escort" in his final moments.

Pratchett delved deeply into the manner and method of our inevitable departure, and to what degree this should be self-determined. While he spoke of the campaign to have the right to die legalised in Britain, he never veered into out-and-out polemic. His tone was personal and inquisitive, and there was enough doubt to give his outlook psychological texture and moral complexity: "I know a time will come when words will fail me, when I can't write my books. I'm not sure I will want to go on living. Is it possible for someone like me and you to arrange for themselves a death that they want?" The question was clearly a wrenching task for Pratchett, who wiped away tears on numerous occasions and asked himself what he would want when it came to the crunch.

Neither was the Dignitas way out a foregone conclusion. One of the company's conditions is that the client administers a deadly poison themselves, rather than have a relative or doctor assist them.

The two men he followed might have ended their life sooner than was necessary, Pratchett argued, so that they could have the death they would eventually want, and so that their families could not be punished for assisting them. "It struck me the reason Peter was going now was to help to protect his wife. If you help someone to die, you may be prosecuted," Pratchett said.

His own Alzheimer's is not yet acute but by the time it is, he may be too late to sign up to Dignitas. "The problem with Alzheimer's is the minute you are ready to die you may not be able to speak. You might have to die earlier than necessary." This seemed to be the case for Andrew Colgan, a 42-year-old with multiple sclerosis who had an evident lust for life but wanted to die this way while he still could.

The most philosophically interesting moments came with Pratchett questioning the principles of voluntary death as it is currently practised. Speaking to Mrs Smedley, his voiceover said: "There is something distasteful about this."

Mrs Smedley's mind had itself wandered to Nazi Germany ("I probably shouldn't say this....") she said, half laughingly, while talking about the similarity of German accents and the Swiss accents of Dignitas staff. Of course, it is not the same thing, yet disabled people were prominent in the Nazis' programme to terminate "lives unworthy of life" and an undertone remains, however unintentional.

Driving to the clinic, Pratchett got a similar disquieting feeling. The clinic was in an industrial estate, and it seems in a sinister way, a little factory of death, set within a cloister of warehouses and manufacturing factories, Pratchett intimated.

There are other uncomfortable moments to offset a simple case for the right-to-die in the Dignitas way. Ludwig Minelli, the head of Dignitas, set it up after coming across Article Eight of the European Convention of Human Rights: the right to self-determination. In keeping with that principle and determining one's end, we were told that 21 per cent of those who went to Dignitas were not terminally ill but had a "weariness for life". And Mr Colgan made a chilling point – albeit, half in jest – before he died: "One day there will be protocol around this," he said, a card perhaps, with the words "Congratulations on your death."

From death to life, and lots of it. At the same time as Pratchett traced last journeys, ITV1 remembered the birth of six baby girls to a Merseyside couple in The Walton Sextuplets. The girls, arriving on 18 November 1983, became a media phenomenon after being declared the world's first female surviving sextuplets.

After being born before a million media flashbulbs, they decided at the age of 18 that they had had enough of the media. Having remained quiet for almost a decade, Hannah, Luci, Ruth, Sarah, Kate and Jeni, were back, aged 27, and once again sharing their experiences of growing up as six. Too much of the narrative relied on rosy nostalgia and cute conversation that failed to penetrate beyond the "happy families" surface.