The dark-haired 22-year-old in black T-shirt, blue jeans and red Crocs is understandably hesitant as he sits at a picnic table in the incongruous setting of a beauty spot somewhere in Israel. We know his name and if we used it he would face a criminal investigation and a probable prison sentence.

The birds are singing as he describes in detail some of what he did and saw others do as an enlisted soldier in Hebron. And they are certainly criminal: the incidents in which Palestinian vehicles are stopped for no good reason, the windows smashed and the occupants beaten up for talking back – for saying, for example, they are on the way to hospital; the theft of tobacco from a Palestinian shopkeeper who is then beaten "to a pulp" when he complains; the throwing of stun grenades through the windows of mosques as people prayed. And worse.

The young man left the army only at the end of last year, and his decision to speak is part of a concerted effort to expose the moral price paid by young Israeli conscripts in what is probably the most problematic posting there is in the occupied territories. Not least because Hebron is the only Palestinian city whose centre is directly controlled by the military, 24/7, to protect the notably hardline Jewish settlers there. He says firmly that he now regrets what repeatedly took place during his tour of duty.

But his frequent, if nervous, grins and giggles occasionally show just a hint of the bravado he might have displayed if boasting of his exploits to his mates in a bar. Repeatedly he turns to the older former soldier who has persuaded him to speak to us, and says as if seeking reassurance: "You know how it is in Hebron."

The older ex-soldier is Yehuda Shaul, who does indeed "know how it is in Hebron", having served in the city in a combat unit at the peak of the intifada, and is a founder of Shovrim Shtika, or Breaking the Silence, which will publish tomorrow the disturbing testimonies of 39 Israelis – including this young man – who served in the army in Hebron between 2005 and 2007. They cover a range of experiences, from anger and powerlessness in the face of often violent abuse of Arabs by hardline Jewish settlers, through petty harassment by soldiers, to soldiers beating up Palestinian residents without provocation, looting homes and shops, and opening fire on unarmed demonstrators.

The maltreatment of civilians under occupation is common to many armies in the world – including Britain's, from Northern Ireland to Iraq.

But, paradoxically, few if any countries apart from Israel have an NGO like Breaking the Silence, which seeks – through the experiences of the soldiers themselves – as its website puts it "to force Israeli society to address the reality which it created" in the occupied territories.

The Israeli public was given an unflattering glimpse of military life in Hebron this year when a young lieutenant in the Kfir Brigade called Yaakov Gigi was given a 15-month jail sentence for taking five soldiers with him to hijack a Palestinian taxi, conduct what the Israeli media called a "rampage" in which one of the soldiers shot and wounded a Palestinian civilian who just happened to be in the wrong place, and then tried to lie his way out of it.

In a confessional interview with the Israeli Channel Two investigative programme Uvda, Gigi, who had previously been in many ways a model soldier, talked of "losing the human condition" in Hebron. Asked what he meant, he replied: "To lose the human condition is to become an animal."

The Israeli military did not prosecute the soldier who had fired on the Palestinian, as opposed to Gigi. But the military insists "that the events that occurred within the Kfir Brigade are highly unusual".

But as the 22-year-old soldier, also in the Kfir Brigade, confirms in his testimony to Breaking the Silence, it seems that the event may not have been exceptional. Certainly, our interview tells us, he was "many times" in groups that commandeered taxis, seated the driver in the back, and told him to direct them to places "where they hate the Jews" in order to "make a balagan" – Hebrew for "big mess".

Then there is the inter- clan Palestinian fight: "We were told to go over there and find out what was happening. Our [platoon] commander was a bit screwed in the head. So anyway, we would locate houses, and he'd tell us: 'OK, anyone you see armed with stones or whatever, I don't care what – shoot.' Everyone would think it's the clan fight..." Did the company commander know? "No one knew. Platoon's private initiative, these actions."

Did you hit them? "Sure, not just them. Anyone who came close ... Particularly legs and arms. Some people also sustained abdominal hits ... I think at some point they realised it was soldiers, but they were not sure. Because they could not believe soldiers would do this, you know."

Or using a 10-year-old child to locate and punish a 15-year-old stone-thrower: "So we got hold of just some Palestinian kid nearby, we knew that he knew who it had been. Let's say we beat him a little, to put it mildly, until he told us. You know, the way it goes when your mind's already screwed up, and you have no more patience for Hebron and Arabs and Jews there.

"The kid was really scared, realising we were on to him. We had a commander with us who was a bit of a fanatic. We gave the boy over to this commander, and he really beat the shit out of him ... He showed him all kinds of holes in the ground along the way, asking him: 'Is it here you want to die? Or here?' The kid goes, 'No, no!'

"Anyway, the kid was stood up, and couldn't stay standing on his own two feet. He was already crying ... And the commander continues, 'Don't pretend' and kicks him some more. And then [name withheld], who always had a hard time with such things, went in, caught the squad commander and said, 'Don't touch him any more, that's it.' The commander goes, 'You've become a leftie, what?' And he answers, 'No, I just don't want to see such things.'

"We were right next to this, but did nothing. We were indifferent, you know. OK. Only after the fact you start thinking. Not right away. We were doing such things every day ... It had become a habit...

"And the parents saw it. The commander ordered [the mother], 'Don't get any closer.' He cocked his weapon, already had a bullet inside. She was frightened. He put his weapon literally inside the kid's mouth. 'Anyone gets close, I kill him. Don't bug me. I kill. I have no mercy.' So the father ... got hold of the mother and said, 'Calm down, let them be, so they'll leave him alone.'"

Not every soldier serving in Hebron becomes an "animal". Iftach Arbel, 23, from an upper-middle class, left-of-centre home in Herzylia, served in Hebron as a commander just before the withdrawal from Gaza, when he thinks the army wanted to show it could be tough with settlers, too. And many of the testimonies, including Mr Arbel's, describe how the settlers educate children as young as four to throw stones at Palestinians, attack their homes and even steal their possessions. To Mr Arbel, the Hebron settlers are "pure evil" and the only solution is "to remove the settlers".

He believes it would be possible even within these constraints to treat Palestinians better. He adds: "We did night activity. Choose a house at random, on the aerial photo, so as to practise combat routine and all, which is instructive for the soldiers, I mean, I'm all for it. But then at midnight you wake someone up and turn his whole house upside down with everyone sleeping on the mattresses and all."

But Mr Arbel says that most soldiers are some way between his own extreme and that of the most violent. From just two of his fellow testifiers, you can see what he means.

As one said: "We did all kinds of experiments to see who could do the best split in Abu Snena. We would put [Palestinians] against the wall, make like we were checking them, and ask them to spread their legs. Spread, spread, spread, it was a game to see who could do it best. Or we would check who can hold his breath for longest.

"Choke them. One guy would come, make like he was checking them, and suddenly start yelling like they said something and choke them ... Block their airways; you have to press the adams apple. It's not pleasant. Look at the watch as you're doing it, until he passes out. The one who takes longest to faint wins."

And theft as well as violence. "There's this car accessory shop there. Every time, soldiers would take a tape-disc player, other stuff. This guy, if you go ask him, will tell you plenty of things that soldiers did to him.

"A whole scroll-full ... They would raid his shop regularly. 'Listen, if you tell on us, we'll confiscate your whole store, we'll break everything.' You know, he was afraid to tell. He was already making deals, 'Listen guys, you're damaging me financially.' I personally never took a thing, but I'm telling you, people used to take speakers from him, whole sound systems.

"He'd go, 'Please, give me 500 shekels, I'm losing money here.' 'Listen, if you go on – we'll pick up your whole shop.' 'OK, OK, take it, but listen, don't take more than 10 systems a month.' Something like this.

"'I'm already going bankrupt.' He was so miserable. Guys in our unit used to sell these things back home, make deals with people. People are so stupid."

The military said that Israeli Defence Forces soldiers operate according to "a strict set of moral guidelines" and that their expected adherence to them only "increases wherever and whenever IDF soldiers come in contact with civilians". It added that "if evidence supporting the allegations is uncovered, steps are taken to hold those involved to the level of highest judicial severity". It also said: "The Military Advocate General has issued a number of indictments against soldiers due to allegations of criminal behaviour ... Soldiers found guilty were punished severely by the Military Court, in proportion to the committed offence." It had not by last night quantified such indictments.

In its introduction to the testimonies, Breaking the Silence says: "The soldiers' determination to fulfil their mission yields tragic results: the proper-normative becomes despicable, the inconceivable becomes routine ... [The] testimonies are to illustrate the manner in which they are swept into the brutal reality reigning on the ground, a reality whereby the lives of many thousands of Palestinian families are at the questionable mercy of youths. Hebron turns a focused, flagrant lens at the reality to which Israel's young representatives are constantly sent."

A force for justice

Breaking the Silence was formed four years ago by a group of ex-soldiers, most of whom had served in Israel Defence Forces combat units in Hebron. Many of the soldiers do reserve duty in the military each year. It has collected some 500 testimonies from former soldiers who served in the West Bank and Gaza. Its first public exposure was with an exhibition of photographs by soldiers serving in Hebron and the organisation also runs regular tours of Hebron for Israeli students and diplomats. It receives funding from groups as diverse as the Jewish philanthropic Moriah Fund, the New Israel Fund, the British embassy in Tel Aviv and the EU.