How Julie brought back memories of a brave woman whose story I told

Fergus Walsh, BBC medical correspondent, tells of his part in the TV dramatisation of the moving story of Anne Turner (starring Julie Walters), who had a rare brain disorder and decided to end her life in an assisted suicide clinic in Switzerland

Watching Julie Walters walk into a grim apartment block on Gertrudstrasse in Zurich brings back powerful memories. I have stood here before, on this exact spot. On a grey January in 2006, I watched Dr Anne Turner enter this building with her three children. It was her final journey. Upstairs, in a nondescript room on the fourth floor, she drank a lethal dose of barbiturates provided by Dignitas.

Anne Turner had a rare brain disorder called progressive supranuclear palsy (PSP). It is a devastating condition in which the nerve cells that control walking, balance, vision, speech and swallowing gradually die. There is no cure. Anne had nursed her husband through the final years of a similar illness and could not face going through the same slow decline, so she chose to end her life in Switzerland.

Anne told me that she would have preferred to die at home in England, at a time of her own choosing and with the help of British doctors, but assisting a suicide is against UK law. Anyone who helped her to die would have been prosecuted and risked imprisonment of up to 14 years. This meant she had to travel to Zurich earlier than she would have chosen to, while she was still physically capable. Whether or not you think what she did was wrong, her courage and determination were plain to see.

Some months later Liz Trubridge, a drama producer, introduced me to the award-winning Irish playwright Frank McGuinness to discuss their plans for a television drama about the final months of Anne's life. I gave them a DVD containing the extended interviews and filming that we had done with Anne in Zurich and at her home in Bath. All the cast and crew were sent copies, and later the director Simon Curtis told me that this material acted like a blueprint when it came to filming.

In September 2008 I met Walters and the rest of the cast for a read-through of the script. Julie had studied the footage of Anne and it was clear that she had already captured both her resolve and her sense of humour. As the reading progressed, her speech began to deteriorate in the intensely moving exchanges with her children and friends. By the end, several people were weeping.

The next time I saw Julie it was to film a brief scene in which I interview Anne about her reasons for going to Dignitas. By now her transformation into the character of Dr Turner was complete.

It was an unnerving experience, like being transported back to the day when I knocked on the door of Anne Turner's bungalow in Bath. I'd spoken several times over the phone to her daughter, Sophie, but not to Anne; she hated talking on the phone because of her slurred speech - another product of her condition. Although I had an idea of what to expect, on our first meeting I was surprised that Anne appeared active and reasonably able. I suppose I'd had an image in my mind of Diane Pretty, who had campaigned unsuccessfully for a change in the law, in a wheelchair with advanced motor neurone disease. She had been completely dependent on her family.

By contrast, Anne appeared to be in the relatively early stages of her degenerative condition. She could walk with a stick and I filmed her chatting over lunch with her children, Edward, Sophie and Jessica. I kept asking myself why a woman in such a close and loving family would want to die. PSP sufferers can live for several years after diagnosis, so why seek death so soon; why at all?

Anne was very clear: "I may look all right, but I'm not. I don't have a good quality of life now. I would end up in a wheelchair and I couldn't see anything or talk. Swallowing is already a problem and I choke a lot. While I still can go to Switzerland, I'm going to go. In a month's time or two, I might not be able to."

Having watched her husband's slow decline, Anne was determined to take matters in her own hands. She was a woman whose mind was made up. Her children were initially appalled by their mother's plans, but once she convinced them that her mind was set they supported her and accompanied her to Zurich. Sophie, Jessica and Edward Turner are now supporters of Dignity in Dying, which is campaigning for the legalisation of assisted deaths in England and Wales.

The process of filming a news story is vastly different from that of a drama - even if it is based on true events. It felt strange re-creating the actual interviews I'd done with Anne. I'm used to being filmed, but not on a large set. When I interviewed Anne in Bath, it was just me and a cameraman. When this scene was shot at a house in Surrey, there was a crew of about 30. I was worried that it would come across as false or staged, but Julie was so convincing it made me feel as if I were talking to Dr Turner again.

I've been a news journalist since 1984 and have covered many distressing stories. You have to keep a certain emotional distance from the events in front of you, otherwise it would be impossible to report objectively. You can care deeply about who or what you are covering, but you must not let your feelings cloud your judgment or prevent you from being an independent observer. On controversial topics, you have to play devil's advocate and ask people direct and often difficult questions. I was pleased that in the screenplay I was not asked to say anything that I hadn't said in real life.

On the morning of her death, I met Anne and her children at the hotel in Zurich. She was having breakfast in her room and we arranged to film her outside before the car took her to the Dignitas office. She told me she wanted the BBC there because people had to see that it was wrong that she needed to go to a strange country to die with dignity. Although I knew the answer, I felt I had to ask her again, on camera, whether there was anything that anyone could say to her to make her change her mind. The answer was no.

A Short Stay in Switzerland does not set out to be simply factual, but to dramatise the events of Anne's life. One of the characters, Claire, is pure invention. Played by Harriet Walter, Claire is Anne's closest friend and is profoundly religious, vehemently against suicide.

Her creation by McGuinness enables him to explore some of the moral issues surrounding assisted suicide. There may well be those who regard the drama as a piece of straightforward propaganda for those who want the law changed. It is not a documentary, and inevitably its sympathies lie with the main character. I would like to hope that a similarly powerful drama could be made about a family that took a different path.

I have interviewed terminally ill patients who are vehemently opposed to assisted dying. I've also spoken to doctors who fear that it would set us on a slippery slope - a right to die might become a duty to die for many frail elderly people who felt that they were a burden to their families.

Whatever your point of view, the drama is powerful and deeply moving. Walters, Stephen Campbell Moore (Edward), Liz White (Sophie) and Lyndsey Marshal (Jessica) are extraordinary in their ability to re-create the Turner family - the conflict, the dark humour and the love. I have kept in touch with the Turner children and last met Edward at the end of October. He'd come into the BBC to be interviewed about the tragic story of Dan James, the 23-year-old who had been paralysed in a rugby accident and had died in Switzerland in an assisted suicide. Edward was sympathetic to the family, but did not feel the law should allow assisted suicide for the disabled; instead it should step back only where patients were terminally ill and had less than six months to live.

Dan's parents, Mark and Julie, had travelled with him. They were at their son's side when he drank the fatal dose. Their family story made unbearable reading, perhaps too unbearable to ever be made into a drama.

Deaths with Dignitas

• Since it was founded in 1998, the Dignitas clinic claims to have helped more than 870 terminally ill people die - an estimated 100 of them British.

• Reg Crew, 74, who suffered from motor neurone disease, was the first Briton to travel to Zurich publicly, his journey followed by a TV crew. The retired car production worker from Liverpool died on 20 January, 2003 .

• The case of Daniel James, 23, from Worcester caused controversy because of his age. A quadriplegic, following spinal injuries caused when a scrum collapsed, he was escorted to the clinic by his parents in last September. His mother said Dignitas had been her son's only viable option. He had attempted suicide three times.

• A Short Stay in Switzerland is broadcast tonight at 9pm on BBC1

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