Perhaps it was her smile, her calmness, or the way even beneath her heavy Islamic clothing that she looked pregnant that quelled his suspicion. And so he relented and let Reem walk unchecked into the main search area with its x-ray machines, computer terminals and wary Israeli soldiers scanning Palestinian workers coming from the Gaza Strip. Two seconds later Reem Raiyshi exploded, killing the guard and three others, and wounding dozens.

Reem Raiyshi was a new weapon of war in the intractable Arab-Israeli conflict . . . the firstever Hamas female suicide bomber.

But why would a young mother like Reem, with two small children, who seemingly had everything to live for, kill herself? How could any woman do that? Male suicide bombers are promised 72 dark-eyed virgins in the gardens of paradise. But what awaits a female suicide bomber on the other side of the detonation?

For the last three years, I have been investigating Reem's life story to try and find out why Palestinian women turn suicide bomber. It is a journey that has taken me into dangerous shuttered cities under military curfew, to the misery of the Gaza Strip, to achingly beautiful Biblical villages and onto the 'Living Tomb' of the world's only jail for failed female suicide bombers.

And it was in that prison, Hasharon, near the Israeli coastal city of Netanya, that as part of a Channel Four documentary Cult of the Suicide Bomber . . . after months of patient negotiation to gain access to this extraordinary prison . . . I finally found the answers from the mouths of these female would-be seekers of paradise.

But the stories I discovered in Hasharon were not tales of glory but of sadness. Of young desperate women who for one reason or another fell victim to the rigid constraints of traditional Arab society. And whose only way out was to blow themselves up.

Hasharon is a forbidding place.

Surrounded by armed guards, barbed wire and barking dogs, the prisoners call it the 'Living Tomb'. To enter Unit 12, you must pass through 10 sets of blue security doors that slam and clank behind you. There are over 100 high-security female prisoners, the majority failed suicide bombers, accomplices or 'senders', women who recruited their best friends for death. All of the women wear hijab . . . long Islamic-style clothing and headscarves that cover their bodies from head to toe. A couple of women even wear face veils with only slits for their eyes.

The prisoners' days are regulated by an endless monotony. Breakfast, exercise for three hours, back in the cell for lunch, exercise in the afternoon, back in the cell at four for the night.

The unit is cramped and damp and the exercise area no bigger than a small school gym. You can pace it out from end to end in 15 steps. To keep fit, some women stroll manically back and forth in the same tiny area during their exercise time.

Most of the women are young, some as young as 13, the majority in their early 20s. The only natural light comes from a hole above the tiny yard . . . and even that is covered in steel mesh.

Most of the women suffer from bad skin due to the lack of sunlight. "I have been here for four years and in all that time I have never seen the moon, the stars or the sun. They keep us locked in as much as possible, " says Kahira Said, 28, the prisoners' deputy leader, serving three life sentences plus 30 years for smuggling a suicide bomber into the heart of Jerusalem.

To break the monotony, the women have begun painting almost childish murals of themselves in fairy-tale landscapes.

The paintings, with their flowers and make-believe thatched houses, imagined windows on the world beyond the walls, are the only images that break up the dull green expanse.

Occasionally, as if to remind the women of their predicament, small sparrows swoop down through the steel mesh of the roof but then . . . unlike the women . . . fly free again.

Amongst the most notorious of those prisoners is 22-year-old Manal Saba'na . . . who recruited her two best friends as suicide bombers. Strikingly beautiful with pale skin and plucked arched eyebrows, Manal was the first girl from her small village, outside Jenin in the West Bank, to leave home and go to university. But university life in Nablus also allowed Manal to join the militant Palestinian faction Islamic Jihad and in secret become a suicide bomber recruiter.

Manal used her own body to transport bulky suicide bomb vests under her Islamic-style clothing. "The vest looks like a waistcoat. It has tall cans filled with explosives. That gave me a headache. And then there are nails and metal pieces. Once I even had to sit an exam wearing the belt as I had no time to get back to my room and hide it. It was very uncomfortable. It was a drawing exam and I could not sit properly, " says Manal.

Manal's first target for recruitment was her best friend Sabrine Abu Amara. Through a careful grooming process, Manal persuaded Sabrine to become a martyr and smuggled another suicide bomb vest into the university in preparation for a martyrdom operation. "After a few days, I told Sabrine to come to my room.

I showed the vest to her. I took it out of my wardrobe. She cried when she first saw it. Cried because she was going to be a martyr and that her time was near, " said Manal, who is serving seven years.

In prison, both Manal and Sabrine remain friends. Both were caught after a male member of Manal's cell betrayed the suicide bomb operation. I wanted to know if Sabrine thought Manal exploited her. "No, she didn't. I was the one who asked her to be a martyr. I wanted to be the one to defend our land, each atom of its dust."

I asked Sabrine if she was scared when she saw the belt.

"No. I was totally motivated.

Every day after, I would wake up thinking: 'Will this be the day?' I was looking forward to it."

But what awaited her on the other side of the detonator? "The male martyr gets 72 virgins but the female martyr becomes queen of those virgins. She will be the best and the most beloved.

The other virgins are maids to her. Life in paradise is quiet, nice.

There are rivers of purified honey, milk and non-intoxicant alcohol, as well as mountains and flowing water. There is everything a man wishes."

In Islam, even in death, women are relegated to second place.

For Manal, recruiting 19-yearold Ayat Kmeil, an old school friend, was even easier. After failing her school exams, Ayat was trapped at home, "unable to leave the house because of the tight religious restrictions of her parents".

Just 18, Ayat's life stretched out before her as closed as a prison cell. Her only option was an arranged marriage . . . in all likelihood to a distant cousin.

In desperation Ayat approached Manal at a family wedding and offered herself as a suicide bomber. Becoming a bomber was probably the first personal choice Ayat ever made in her life.

But Ayat's would-be martyrdom shocked and angered her parents. In Arab society, a woman's "honour" extends beyond her death. By blowing herself up, a woman inevitably "exposes her body to strangers", a cultural taboo.

"In our religion, it is forbidden for a girl's body to be smashed and collected by Jews. A girl should cover herself up at home, so how can she uncover herself outside?" asked her father Ahmed Kmeil, a religious teacher.

Far from being proud of Ayat, he vowed that when his daughter returned from serving her fouryear prison sentence she would never leave the house without her mother beside her. "If I had known what she was planning, I would have told the Jews."

But for other women, the path to martyrdom is the only escape route from some dishonour in this earthly life.

In her official Hamas propaganda video will, Raiyshi, a 22year-old mother of two, said she wanted to knock on "heaven's door with the skulls of the sons of Zion". The organisation also released dozens of pictures of Raiyshi playing with her young children . . . Doha, three and Mohammed, 18 months . . . taken days before her death. In the pictures, Raiyshi poses with a gun and comforts the children whilst wearing the green Hamas bandanna that symbolises her forthcoming suicide bombing.

But it soon emerged that Raiyshi's actions were, horrifically, really an act of atonement for adultery. She had been having an affair with a friend of her husband, Ziyad, and may even have been pregnant with her lover's child.

For women who transgress this Islamic honour code and 'shame' their family there is only one punishment . . . death. Usually, male relatives stab or shoot their sister. Every year, up to 30 Palestinian women are killed in this way. Their killers are rarely arrested and never prosecuted.

According to Israeli intelligence reports, after the discovery of the affair, both Reem's lover and her husband together decided that the best option for her was 'martyrdom'.

In her martyrdom will, Reem even gives a clue to the real reason for her impending death.

"Martyrdom purifies you from any sin. So the grave's agony will be lifted from the martyr's shoulders and there will be no punishment whatsoever on the day of judgement." There is only one crime in Arab culture that would damn a young mother . . . adultery.

Forty days after her death, the minimum mourning period in the Islamic tradition, her husband Ziyad remarried and stripped away all the pictures of his former wife. It was hardly the actions of a loving husband celebrating his 'martyr wife'.

'Honour' determines every part of women's lives in Arab society, even the manner of their death. Hasharon is one of the saddest places I have ever been.

Sad because of the lives lost there, but sad also because it is a living testament to the price these women have paid for defying both their own and Israeli society. Trapped and suffocated in their family homes, and bound by the Arab social codes that restrict their freedom, these women chose death as an escape.

And perhaps the saddest thing of all is that Hasharon, with its bars and cells, is still the most free place they will ever be in their lives.

'Cult of the Suicide Bomber' will be shown on Channel Four on 18 September at 8pm