A Palestinian child plays near his home in the Rafah refugee camp, in the southern Gaza Strip. (Maan Images)

It is one of the poignancies of Tom Hurndall's short life that he had gone to Gaza in search of a story, and ended up becoming it. A 21-year-old photography student at Manchester Metropolitan University, he went to Baghdad in February 2003 to photograph human shields, activists who were trying to protect ordinary Iraqis from the threat of Anglo-American attack. While he was there he heard about Rachel Corrie, a 23-year-old American peace activist with the International Solidarity Movement (ISM), who had been protecting a Palestinian's family's house in Rafah, in the southern Gaza strip, when an Israeli bulldozer crushed her to death. Tom went to Gaza to find out what had happened.

All that is clear from the book his mother, Jocelyn, has written about Tom's life, and about his family's battle to bring the Israeli army to account for killing him. It's not a political book, she stresses, though the anger, frustration and disappointment she feels towards the army, and the Israeli and British governments, is obvious.

Tom was in Rafah, in the Israeli-occupied Gaza strip, on April 11, at an ISM demonstration. Suddenly low shots were fired from an Israeli army watchtower in the direction of children playing on a mound of rubble. Most of them ran - but three froze. Tom, wearing a bright orange ISM jacket, ran to help them. He scooped up a boy and carried him to safety. He ran back for the two girls, bent down to put his arm round one of them and was shot in the head.

Jocelyn was at work, at a school in London where she was head of learning support, when she got a call from her daughter Sophie saying that Tom had been shot. It was the last day of the spring term. She calmly finished photocopying a report she had been working on and distributed it into pigeonholes, before setting off for home. It was as if she was trying to put off discovering the full horror of the story. "I think you do anything to delay the moment of impact," she says in the bright sitting room of her north London home.

After nearly two months by his hospital bedside in Israel, the family - Hurndall, her former husband, Anthony, and their children Sophie, Billy and Fred - were allowed to bring Tom back to the UK. The brain injury had left him in a coma; his main organs working, but nothing else. Did she accept that Tom would die from the start? "I think I knew," she says. "The pressure in Tom's head had damaged other parts of his brain. I knew he would never recover."

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Tom eventually died nine months later on January 13 2004 - Jocelyn's birthday - in hospital in London. Was it a relief, in a way? "It was, because he wasn't in pain any more," says Hurndall. "But it was also impossible when he died." She is silent for a long time. "I still haven't accepted it."

Hurndall is softly spoken with gentle, pale blue eyes. She seems fragile but with an intense strength. She's a battler but seems surprised by it. She tells of the time she met Tony Blair at a dinner. "I remember saying to him, 'You've hurt me'. I couldn't imagine saying that to anybody five years ago." She laughs at this. "This middle-class mother coming out with these strident things." Tom's death has changed her. "You develop this language when there's this anger. I'm not usually a strident person, I've never needed to be."

Her book is called Defy the Stars, words Tom had tattooed on his wrist. They come from Romeo's cry "Then I defy you, stars!" in Romeo and Juliet, and seemed to say a lot about his attitude to life. Hurndall says she finds herself carrying her book around the house, "because it's what's left of Tom. It's my gift to Tom, it's my gift from Tom."

Apart from the anger and the love and the pain, one of the strongest senses in the book is that of discovering Tom, as his mother has since his death. She read his journals and pored over his photographs. Tom was young and idealistic, but he also knew how dangerous it would be to go to Iraq and Gaza. "He was very mature in many senses," says Hurndall. "He was aware of the risks, but his desire to see and question and be curious was greater. People are surprised to read that Tom considered the possibility of being shot. I gulp when I read it, but I understand that of course he would consider it. If you're there, it's on your mind all the time."

She didn't want him to go to Baghdad but she knew she couldn't stop him. "I couldn't condone it. I felt angry with Tom and a terrible worry that weighed me down and affected me every minute he was away. I was numb, anaesthetised, blank. I kept expecting him to come home. I think he would have left Rafah within 48 hours of his final entry in his journal." His final entry was on the morning of the day he was shot.

From the beginning, the Hurndalls worried that there could be a cover-up. The first news reports, heard by an Israeli friend on the radio station Kol-Israel, said a man wearing military fatigues had been shooting at a watchtower. "Even days later no one from the Israeli army or Israeli government had been in touch with us," says Hurndall. "So that in itself spoke volumes. We really felt this draught of silence." At the hospital, one doctor suggested that Tom's head injury "was commensurate with a blow from a baseball bat", even though on his notes it clearly said "gunshot wound", with an entry point and exit point - as though someone was suggesting that the injury had been caused at close range and so not from the watchtower.

To read the full article please visit The Guardian.