Female circumcision will be inflicted on up to 2,000 British schoolgirls during the summer holidays – leaving brutal physical and emotional scars. Yet there have been no prosecutions against the practice

Like any 12-year-old, Jamelia was excited at the prospect of a plane journey and a long summer holiday in the sun. An avid reader, she had filled her suitcases with books and was reading Harry Potter and the Prisoner of Azkaban when her mother came for her. "She said, 'You know it's going to be today?' I didn't know exactly what it would entail but I knew something was going to be cut. I was made to believe it was genuinely part of our religion."

She went on: "I came to the living room and there were loads of women. I later found out it was to hold me down, they bring lots of women to hold the girl down. I thought I was going to be brave so I didn't really need that. I just lay down and I remember looking at the ceiling and staring at the fan.

"I don't remember screaming, I remember the ridiculous amount of pain, I remember the blood everywhere, one of the maids, I actually saw her pick up the bit of flesh that they cut away 'cause she was mopping up the blood. There was blood everywhere."

Some 500 to 2,000 British schoolgirls will be genitally mutilated over the summer holidays. Some will be taken abroad, others will be "cut" or circumcised and sewn closed here in the UK by women already living here or who are flown in and brought to "cutting parties" for a few girls at a time in a cost-saving exercise.

Then the girls will return to their schools and try to get on with their lives, scarred mentally and physically by female genital mutilation (FGM), a practice that serves as a social and cultural bonding exercise and, among those who are stitched up, to ensure that chastity can be proved to a future husband.

Even girls who suffer less extreme forms of FGM are unlikely to be promiscuous. One study among Egyptian women found 50% of women who had undergone FGM "endured" rather than enjoyed sex.

Cleanliness, neatness of appearance and the increased sexual pleasure for the man are all motivations for the practice. But the desire to conform to tradition is the most powerful motive. The rite of passage, condemned by many Islamic scholars, predates both the Koran and the Bible and possibly even Judaism, appearing in the 2nd century BC.

Although unable to give consent, many girls are compliant when they have the prodecure carried out, believing they will be outcasts if they are not cut. The mothers believe they are doing the best for their daughters. Few have any idea of the lifetime of hurt it can involve or the medical implications.

Jamelia, now 20, who says her whole personality changed afterwards."I felt a lot older. It was odd because nobody says this is a secret, keep your mouth shut but that's the message you get loud and clear." She stopped the sports and swimming she used to love and became "strangely disconnected with her own body". Other girls have died, of shock or blood loss; some have picked up infections from dirty tools. Jamelia's mother paid extra for the woman to use a clean razor. It is thought that in the UK there are one or two doctors who can be bribed by the very rich to to carry out FGM using anaesthetic and sterilised instruments.

Comfort Momoh works at Guy's and St Thomas' Hospital in London, in one of the 16 clinics up and down the country who deal with FGM and its health repercusssions. Women who have had much of their external genitalia sliced off and their vaginas stitched closed, but for a tiny hole, also come to be cut open in order to give birth.

There are four types of female circumcision identified by the World Health Organisation, ranging from partial to total removal of the external female genitalia. Some 140 million women worldwide have been subjected to FGM and an estimated further two million are at risk every year. Most live in 28 African countries while others are in Yemen, Kurdistan, the US, Saudi Arabia, Australia and Canada.

The UK Prohibition of Female Circumcision Act 1985 makes it an offence to carry out FGM or to aid, abet or procure the service of another person. The Female Genital Mutilation Act 2003, makes it against the law for FGM to be performed anywhere in the world on UK permanent residents of any age and carries a maximum sentence of 14 years imprisonment. To date, no prosecutions have been made under UK legislation.

"Obviously in summer we get really anxious. All activists and professionals working around FGM get anxious because this is the time that families take their children back home. This is the time when all the professionals need to be really alert," said Momoh.

"There is no hard evidence in figures about what is happening in the UK because it's a hush-hush thing. It's only now that a few people are beginning to talk about it, which is good because change will only come from within and the numbers coming forward are rising. But there is a lot of family pressure. When I first started in 1997 we had two clinics in the country, now we have 16."

One woman told the Observer how a midwife examining her had raced retching and crying from the room. She had no idea she was "abnormal" before that happened. There is a clear need for women who have suffered FGM to be able to visit health professionals who understand what has happened to them. Momoh said that for those who wanted it, some surgical reversal work could sometimes be done on women with the most severe FGM procedure, Type III. For those with other types, counselling and support is all that can offered.

"Periods are agony – you get a lot of women who are determined to have reversals while they are having their period but then when the pain has stopped they lose their nerve again," said Leyla Hussein, 29, who has had to have years of counselling to cope with her own anger and distress at what was done to her as a child. It has helped her forgive her own mother's complicity in the mutilation she endured, though the older woman could not understand why Hussein would not have her own child, now aged seven, cut. But Hussein has vowed that she will be the last generation of women in her family to suffer.

"It was my husband who said on our honeymoon, 'We are not going to do this thing to any child of ours.' I was quite shocked, I hadn't questioned it. But I now realise a lot of men are not in favour of FGM, not when you tell them the woman is not going to enjoy herself."

Hussein is among a slowly but steadily growing band of women who have reacted against what happened to them with courage and a determination to stamp out FGM. Hussein has run support and discussion groups for affected women and for men, and formerly worked at the African Well Women's Centre in Leyton, east London.

"I can really relate to some of the women who are very angry, but how do you blame your mother, who loves you yet planned this for you? There is a lot of anger and resentment. Many women blame themselves and of course there are flashbacks to deal with. I had blackouts – anytime I had to have a smear test, I would pass out because lying in that position brought it back to me, but the nurse is used to me now and allows a little more time with the appointment."

"The new generation, born and raised here in Britain, they are used to expressing their views and it will be a lot harder to shut them up. Last month was the first ever march against FGM [in Bristol where 15 to 16 mothers protested] and that is a sign of something new."

Asha-Kin Duale is a community partnership adviser in Camden, London. She talks to schools and to families about safeguarding children. "Culture has positive and negative issues for every immigrant community. We value some traditions, and most are largely good.

"FGM is not confined to African countries. It has no basis in Christianity, it has no basis in Islam; none of Muhammad's daughters had it done. For some parents it is enough to let them know that and they will drop it completely. Everyone needs to understand that every child, no matter what the background or creed, is protected by this law in this land."

She said there needed to be an understanding of why FGM took place, although that was not the same as accepting that the practice had a cultural justification.

"FGM has a social function and until this is understood by social services and other bodies they will never stop it. It is a power negotiation mechanism, that women use to ensure respect from men. It prevents rape of daughters and is a social tool to allow women to regain some power in patriarchal societies. With girls living in the UK there is no need to gain the power – it has to be understood that girls can be good girls without FGM."

For Jason Morgan, a detective constable in the Met's FGM unit, Project Azure, the solution lies with those girls themselves: "Empowering youth, giving them the information, is the way forward. They are coming from predominantly caring and loving families, who genuinely believe this is the right thing to do. Many are under a great deal of pressure from the extended families.

"Sometimes it might be as simple as delivering the message of what the legal position is; sometimes we even give them an official letter, a document that they can show to the extended family that states quite firmly what will happen if the procedure goes ahead. The focus has to be on prevention."

Project Azure made 38 interventions in 2008, 59 in 2009 and 25 so far this year. For Morgan those statistics are just as important as getting a conviction. "We know it happens here although we have no official statistics, but we have seen very successful partnerships and we don't want to alienate communities through heavy-handed tactics.

"While a prosecution would send out a very clear message to practising communities, really it is very difficult and you would be relying on medical evidence, and in turn that would all hinge or whether the child consents to an examination."

But Naana Otoo-Oyortey is not so content with the softly-softly approach: "We have anecdotal evidence that it is being done here. So someone is not doing their job: it's an indication that the government has been failing to protect children. The commitment is hollow."

Head of the leading anti-FGM charity Forward UK, Otoo-Oyortey said people value the FGM tradition as something which holds a community together and gives it structure. "It's seen as a party, a cutting party because it's a celebration – people expect it as a way of welcoming a girl. A lot of women will mention to us that there have been no prosecutions here so why do we worry about the law? At the end of the day who will know?

"And we cannot just blame the women as the men are silently supporting it by paying for it. The new government's lack of a position on FGM is very worrying. We don't know what they will do, but we do know that the summer holidays are here again and we will be left to pick up the pieces in a few weeks' time."

And for those who will be "cut" this summer, the effects will be lifelong. Miriam was six when she had her cutting party at her home in Somalia, two years before war arrived to force her family out.

When she was 12, doctors were horrified to find that what they thought was a cyst in her body was actually several years of period blood that had been blocked from leaving her body. Unable to have children, she now lives and works in England and worries about other girls. "I'd seen so many people circumcised, all my neighbours, so I knew one day it was going to happen to me. We knew what was happening," Miriam said.

"The little girls who were born in Europe have no clue. They will be traumatised a lot more. The only thing they know is that they are going away – that's what they say, 'We're going on a holiday'.

"Then her life and her head are going to be messed up. It's amazing how many people are in mental health care because of their culture. Don't get me wrong, I have religion and culture and I love where I'm from and I love what I stand for. But culture should not be about torture.

"Why would anyone want to go and cut up a seven- or eight-year-old child? People need to wake up — you are hurting your child, you are hurting your daughter, you're not going to have a grandchild, so wake up."