I had to hold my 17-year-old son down on the bed after he heard the news. His strength really shocked me. I was gripping his upper arms as tightly as I could to hold him flat on the bed, but he was spitting with rage, tears streaming down his face. I was shouting, "Stop! Please stop!" but he was pushing up at me hard, his face twisting like his body underneath me. He was fighting with everything he had in order to be able to get up, run down the stairs and get out of the house. All I knew at that moment was that I couldn't let him leave. We were in his bedroom in London and I had just given him the news that his grandmother had been blown to pieces by a rocket in Israel. Jordy had lost his other grandmother five months earlier to cancer. This time there was someone to blame.

Our pain and his rage opened a window up for me on to what is happening in Gaza. There are thousands and thousands of young men who have experienced - or are experiencing - that rage in Gaza and the West Bank, and their fathers and grandfathers have no doubt experienced it too. When I heard in the days that followed Shuli's death that they handed out sweets in Gaza to celebrate the fact that the rocket had hit a target, I was appalled. Now with all I have seen over the last two weeks in Gaza, part of me feels: why wouldn't they celebrate?

Shuli, my wife's mother, lived on Kibbutz Gvar-am, which lies 5km to the north of Gaza and 10km to the south of Ashkelon. She had been the kibbutz nurse until she retired and lately had worked part-time in the kibbutz factory making envelopes for the Salvation Army and Asda. In May last year she had been expecting a visit from a cousin who was over from America. The cousin had phoned to say that she was too frightened to come to Shuli's kibbutz on account of a rocket landing in Ashkelon the previous day. "Don't worry," Shuli told her, "every missile has its own address. We'll come to you instead."

An hour later she arrived at the house where her cousin was staying. Her son, Yariv, rang the doorbell and while they waited for someone to answer, Shuli stepped away in order to get some shade next to a wall. The rocket came out of nowhere and she died instantly. None had landed in that area before. Only later did we find out that Shuli had rung her sister the night before her death and made her promise to look after her children if anything were to happen to her. It was beshert - meant to be.

That was six months ago and now, sat at home in north London with the Israeli bombardment of Gaza well into its third week, and with news of fresh horrors arriving daily, our house is filled with a despair of a different kind. It has felt like a house in mourning again. A dark fog which I can't really describe has enveloped us. Maybe it's shame. I don't know. I know we all felt relief that Israel didn't retaliate after Shuli was killed. But it's happening now. I keep looking at Shuli's birth certificate which my wife now has. Shuli's mother had left Germany by boat for Palestine after Hitler came to power and she helped form a radical socialist community on land partitioned to the Jews by the British. Shuli's birth certificate states her nationality as Palestinian. Her death certificate said Israeli.

My wife says she feels scared and lost and full of guilt. "It's my country and I see myself as Israeli not Jewish," she keeps shouting at me. Does that make you feel better or worse about what's going on, I ask? "That's worse!" she says, "because Israel is nothing to do with God." I digest this, but don't even know where to begin to start unravelling that statement.

I'm trying to think back to Christmas when I was staying on the kibbutz. I'm struggling to remember what I felt as the Hamas rockets were flying in every day during the week before the Israeli F16s screamed over our heads and began pounding the Gaza Strip and those condemned to live within it. My five-year-old son, Geffen, was constantly asking me if he was going to die like his Grandma. People on the kibbutz rallied around as you would expect; it was no time for questions or politics. We didn't see the bigger picture. But on returning home, I saw it all too clearly, and it sent me into meltdown.

I feel guilty about abandoning my friends on the kibbutz - not physically but mentally. A good friend of mine over there called Mirav, whom I've known for 25 years, has a 12-year- old daughter, Omer, who just stays in her room and cries. She's been doing it for three months now and this all began after the fourth Kasam rocket hit her school. I try to think about her, but shockingly she doesn't seem to matter so much any more. Not at the moment anyway. Not from here in England with what we're seeing on television every day. Everything is dwarfed by the horrors in Gaza.

I'd seen the ground troops massing up the road from the kibbutz towards the border with Gaza in the days before I left Israel, but I never believed for one second that they would go in. They did. In the last few days, I've stopped watching television and buying newspapers. For the first time in my adult life I don't want to know what is going on outside my own front door.

Most Israelis I know think Hamas wants to annihilate Israel. A lot of Jews over here think that too. I don't know if that's what Hamas wants: it depends what you read. I was over there when they blew up buses on Dissenghof Street in Tel Aviv in 1996. That act seemed to turn Israel right wing just at the moment the country was mourning the death of Rabin and was, I believe, genuinely committed to peace. But Hamas is now part of the political process whether Israel, Britain and America likes it or not and dialogue is the only way forward. Would hatred for Israel stop if it were to return to its 1967 borders? Of course not, but Israel has to do it anyway. It has to do the right thing, to help build a strong Palestinian state where people can live normal lives, work, feed their kids, be happy, safe, have dignity. That's what most people want in life isn't it?

At Shuli's funeral last May, her son Jonathon, my brother-in-law, gave a speech. "Where are the doves?" he asked. "What is this land worth without someone with a vision? Nothing. Without doves it wasn't worth the struggle." Jonny is 34. He's an army reservist who is studying to be a neurologist and has a two-year-old son called Boaz. He didn't scream for blood at his mother's graveside, he screamed for peace.

In our house we have our own thinking to do. My eldest son, Jordy, has Israeli citizenship and in two years he will have to choose either to relinquish that citizenship or to fight in the Israeli army. It can be only his choice. But, unlike the Palestinians in Gaza, at least he has one.