Eye witness: It takes training as well as nerve to be a human shield

In an East End hall, volunteers learn to beat Israeli tanks with wallpaper paste

'Not everybody has to jump in front of tanks," says Leila, a young Palestinian, who will only give us her first name. Nervous laughter breaks out among the 60 people in this gloomy hall in east London, where Gandhi once slept. They are here to learn how to be human shields, trying to prevent Israeli tanks and jets firing at homes in refugee camps on the West Bank. Later there will be a session on "dealing with tear gas, sound grenades, remaining sane etc".

These British volunteers intend to join the Freedom Summer, a series of non-violent direct actions against what they perceive to be an occupying army. Come July, they expect to be looking down the barrel of a gun, or at the walls of an Israeli jail cell, like Josie Sandercock, the medical researcher from Birmingham who is currently on hunger strike in Tel Aviv.

The 32-year-old was arrested last Saturday when the Israeli army moved into a camp in Nablus. Other members of her international group are being deported but Ms Sandercock insists she has done nothing wrong and plans not to eat until her appeal is heard. That could take a month.

"Josie believes in doing everything totally and intensely, and I fear she will approach this in the same way," says Dr Amanda Burl, her colleague and friend. "We went to a peace rally together in Trafalgar Square after 11 September and she met some people from Palestine. The more she heard and read about what was happening the more angry she became, and the more frustrated at not being able to do anything."

The same goes for most of those around me. Some are veterans of Genoa, Faslane, and even Greenham Common; others have never done anything like this before. "We are not dealing with the Metropolitan Police on a May Day action," warns Chris, an activist with the International Solidarity Movement. Those who go to Israel will have to follow ground rules: no violence, no abusive language, no weapons, and no alcohol or drugs during actions. "This is the army. If you hit a soldier and they start shooting people, you have brought that on all the others."

Nobody here is using their surname. The registration list asks only for an email address. No photos are allowed to be taken. Photocopied handouts give advice on how to deal with the psychological trauma of being arrested and searched.

Chris shows a slide of protesters confronting a tank that has shot a man dead, and pasting it with posters of his face. "They didn't do anything to stop us," he says. "They basically retreated, because they did not want confrontation with internationals that time. We managed to break the siege of Nablus with a brush and some wallpaper paste."

The conflict had intensified by Easter, when the comedian Jeremy Hardy was part of an ISM group stuck in Bethlehem as Israeli tanks rolled in. The violent truth of what they are getting into hits people as we watch video footage of the trip, which is meant for broadcast but has never been shown before.

"The human shield is not something the Israelis are going to respect," says Hardy on film, after seeing shell holes in the maternity wing of a hospital. Next we watch his group being shot at. "I thought they were rubber bullets," says Hardy with panic in his voice. "They are not, they are live rounds. They are firing into the ground in front of people but the ricochets are hitting them."

Several volunteers are wounded. The film ends with the group in a hotel besieged by snipers, hoping for their embassies to get them out. "There is a lot of bloodshed down in the town," says Hardy. "There are bodies in Manger Square, a woman is dead. The plucky Brits in the hotel are not the story – it's out there, where people are injured or dying."

The international Solidarity Movement was founded a few years ago as a network of people from Britain, Italy, France and US, prepared to engage in non-violent direct action. Some are in Israel today. "We are always labelled peace activists. I find that quite frustrating," says Chris. "We are justice activists. ISM believes that if there is justice and the occupation is ended then peace will follow."

On Saturday afternoon we huddled together in "affinity groups" and discover how difficult it is to make split-second decisions democratically. The training session in non-violence degenerates into a fierce argument about fighting back. "Suicide bombers are victims too," says a woman, and nobody dares contradict her. In this room, the complex conflict is distorted into good versus evil. In every role play, the villains are always the same: dangerous soldiers and irate settlers.

Listening to Israel repeatedly branded "a terrorist state", I remember eating a Sabbath meal with a Jewish family a few months ago, and imagine the fireworks if they were in the room. The eldest son, Warren, was thinking of volunteering to fight in the Israeli army. The committment required to join either side leaves little room for doubts.

Jill got involved with the Palestinian Solidarity Campaign when she retired from her full-time job as a teacher a year ago, and went to Ramallah in December. "I spent my 36th wedding anniversary lying on the floor in front of an Israeli tank," she says.

She is not so sure Nablus was really liberated by the fly posters, nor that demolishing road blocks achieves much except the erection of replacements a way down the road, but still thinks people should go.

"The effect on Palestinians of having foreigners with them who understand what is happening and care about it is marvellous," she says.

Anna, a 30-year-old secretary from London, intends to give up her job to go out with the group for a month. We eat falafels and discuss the advice not to wear sun cream on your face, because tear gas sticks to it and burns. Anna admits she would probably not go on hunger strike like Josie Sandercock, but thinks she is ready to be jailed, and deported. "If that is the worst that can happen, I will be ready. I hope." So too will the soldiers, perhaps including their British volunteers.