It was lunchtime. There was nothing to distinguish the apartment block or the plain room within it. The colours were neutral, the furniture a single bed and a table holding a vase of flowers. On the bed a 30-year-old man drank a draught of liquid. It was bitter so immediately afterwards he had a piece of chocolate.

“I lay beside him and chatted,” says Laura McDaid. “I said, ‘How do you feel?’ He said, ‘Happy’. I think he did. I hope he didn’t say that just for me. After about a minute he stopped talking.”

By the time Martin Barry took his life in the clinic run by Dignitas in a suburb of Zurich his physical condition was poor. In 2002 doctors had diagnosed an aggressive form of secondary progressive multiple sclerosis; by April 2005 he was unable to walk, he had tremors, his eyesight was failing and he had an infected bedsore on his back that embarrassed him because of the smell. He was in great pain, he was incontinent and he knew that living alone with a visiting carer would not be an option for much longer. Faced with a choice between further deterioration over perhaps another year in a care home, and managing his death, he chose the latter.

“He didn’t want to die in Switzerland, in an unfamiliar apartment,” Laura explains. “He wanted to die at home with his family and friends around him, but that wasn’t going to happen.”

Martin lived in Cork, Ireland, where the law on assisting suicide is similar to the UK. At the Dignitas clinic 115 Britons have ended their lives and although it is illegal to help terminally ill people carry out the act painlessly, none of those who have accompanied them have been prosecuted.

Laura accompanied Martin because she respected rather than condoned his choice and because she did not want him to die alone. She stresses that in talking about his illness and death she is not advocating assisted suicide or euthanasia. Rather, she is telling a story — for her a profoundly emotional one — that has had such a searing effect on her that it has become the foundation of an eloquent - and fictional - play that she has written for Radio 4.

She met Martin in January 2001; both were newspaper journalists working in Dublin. She was 23 and had grown up in a supportive middle-class family in Coleraine, Northern Ireland. Martin was adopted and had grown up on a council estate in Cork and, at 26, he was handsome and had the force of someone who wanted to be noticed. He challenged Laura; she was entranced and soon they were in love and living together.

“He was a huge character,” she says, speaking in Belfast where she now works for the BBC. “He had views on everything, he was passionate about journalism and he was happiest when he was the centre of attention. He was funny and he battled MS with humour and strength.”

The diagnosis was a shock. He had tried to ignore, and even deny, symptoms over several years. “I could see him losing weight, he’d sometimes lose control of his bowels and bladder, he was thin and frail and had trouble walking,” Laura says. “He was in a wheelchair within three months. The prognosis was pretty bad but he tried to be upbeat. I was his carer and we were both able to work part-time. But it got worse and I found that emotionally very hard.”

In 2004 Martin was told that he probably had two years to live and that it was likely that, having lost the ability to swallow, he would choke to death. “He got frustrated not being able to do the things that he loved doing,” Laura says. “He was gregarious, he loved being out, loved a drink. He couldn’t do any of that any more.” Neither could he be active in the profession from which he had drawn his sense of identity. “He wrote when he could but he didn’t have the energy to go out on stories. He felt that everything around him was just as it used to be but that he was an outsider looking in on it. He didn’t feel part of the world as it was.”

This sense of isolation affected both of them. Some friends found his disability hard to witness, and Laura blames herself for her inability to support him full-time. “He got more and more depressed and that put a strain on us. We already had a volatile relationship — he was a volatile character! — and our relationship became more like carer and patient than the way it had been. I felt that I didn’t have anything to talk about because we were living in this enclosed world.

“I left in April 2003. I felt guilty because I was leaving my best friend to cope with that, and I loved him. He was so angry at me and felt betrayed but he came to realise that we hadn’t been helping each other. We became much better friends after that.”

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