Nina Lakhani: Tony Nicklinson wanted to die, but he also wanted to leave a legacy in law

Within a few months of his stroke, Tony Nicklinson talked of wanting to die. His family knew locked-in life would never be enough

Tony Nicklinson's fight for the right to die was never just about himself. He wanted to die – he'd been sure about that for five or six years. But at the heart of his fight was a fundamental question: who has ultimate power over life, an individual or the state?

His death yesterday morning came as a shock to most of those who followed his case. We knew his health had deteriorated in recent weeks and that he was suffering more pain and discomfort than before, but there was no suggestion of anything life-threatening. In fact, last week he told me that he would take his fight to the Court of Appeal, and higher if necessary, after three High Court judges ruled against his bid to be legally assisted to die.

But it seems that last week's decision took the fight out of him. He refused food and went rapidly downhill over the weekend, having contracted pneumonia. One of the last things he did was prepare a message to send out over Twitter in the event of his death. In June, he told me by email that he might become the first person to say a formal goodbye on Twitter, after becoming the first person with locked-in syndrome to use the social-networking site. Mr Nicklinson suffered a catastrophic stroke in 2005 which left him unable to move any part of his body voluntarily apart from his eyes and eyelids. At first, he thought he would get better, but after a few months, when he realised there was no recovery, he started "talking" about wanting to die.

His family was not surprised. His wife, Jane, told me that they knew such an existence would never be enough for him. But at the time he agreed to give it a couple of years, promising his wife and two daughters, Beth and Lauren, that he would try to adapt and learn to cope. But he couldn't.

He could have asked his family to help him travel to Switzerland to the Dignitas clinic, and I'm sure it would have, but that would have been like admitting defeat. "Why should I?" he once asked me. "Why can't I die at home, in my own country, when I choose?"

I'm glad he at least got to die at home, with his family around him, but I think he probably reached the end of his life disappointed and angry that he didn't succeed in changing the law – leaving others behind to fight for something he had started. His family has lost an incredible man – a fighter, a human-rights defender, someone who believed he could change the world for the better, and it is rightly very proud.

The Nicklinsons weren't great talkers – like in many families, worries or gripes often went unsaid. Ms Nicklinson once told me that looking back to the months before her husband's stroke, there were hints or signs of something being amiss, but nothing was ever said. So even though the couple very publicly fought for Mr Nicklinson's right to die, his wife said they had never properly discussed what it would be like, for her or the girls, if the time came. They will never have to face that day now and the family will have to learn to live again, without him.

For the last seven years, Ms Nicklinson's existence has centred on her husband's needs. They only moved back to England after his stroke, having spent their whole married life as expats in the Middle East, Malaysia and Hong Kong, and there has been little time, or motivation, for her to make new friends.

The desperate anguish written on Mr Nicklinson's face last week when he was told he had lost his case will haunt people, whether they agreed or disagreed with his fight. I will never forget his pained face, his grief for the life he once had and for the man he once was, or his burning determination for the right to be able to die with dignity.