Parents will be prosecuted if they fail to prevent their daughter being cut, and all victims of female genital mutilation (FGM) will get lifelong anonymity, David Cameron will say on Tuesday.

As the prime minister hosts a Girl Summit with Unicef aimed at mobilising domestic and international efforts to end FGM and child marriage, new measures will be announced aimed at ending the practices "once and for all".

The announcement comes the day after it emerged that the number of women living in England and Wales who have been subjected to FGM is twice as high as previously thought. A new study reveals more than 137,000 women in England and Wales are living with the consequences of FGM. The number has significantly increased in the past 10 years as women flee war-torn countries to find safety in Britain, according to the report from City University and the human rights group Equality Now.

To mark the first Girl Summit in the UK, the prime minister will announce a change to the law that will make it parents' responsibility to protect their daughters from FGM or face punishment. Currently it is against the law to cut a child in Britain or take a child out of the country for the purposes of FGM, but this new law will extend sanctions.

Cameron will also launch a £1.4m "prevent programme" to help stop the practice being carried out on girls and to care for survivors, and he is expected to unveil new police guidance on how to handle new cases, and a consultation on civil orders to protect those at risk of FGM.

A new specialist FGM service, which will include social services, will identify those at risk of being cut. Cameron will say: "All girls have the right to live free from violence and coercion, without being forced into marriage, or the lifelong physical and psychological effects of female genital mutilation. Abhorrent practices like these, no matter how deeply rooted in societies, violate the rights of girls and women across the world, including here in the UK."

The new study reveals that in England and Wales about 103,000 migrant women aged 15 to 49, 10,000 girls under 15 and about 24,000 women aged 50 or above had been subjected to FGM. The numbers of women from the Horn of Africa – where the most extreme form of FGM is common – had increased by 32,000, while the number of women from east and west Africa also increased by 10,000 over the past decade.

A 2007 report using 2001 census data stated that 66,000 women and girls had been subjected to FGM in England and Wales with an estimated 24,000 girls under 15 at risk. Until now the most recent study, funded by the Trust for London and the Home Office, does not estimate the number of at-risk girls, but reveals 60,000 girls under 15 were born in England and Wales to mothers who had undergone FGM between 2001-11.

Earlier this year, the then education secretary, Michael Gove, agreed to write to headteachers about the dangers of FGM after 250,000 people joined a campaign backed by the Guardian and change.org in the runup to the summer holidays when many girls are sent away to be cut.

Efua Dorkenoo of Equality Now said the government had made positive steps but professionals needed clear guidance to identify at-risk girls and give them help. "The government needs to get a handle over this extreme abuse of the most vulnerable girls in our society by implementing a robust national plan to address the issue," she said.

"There is no time to waste on platitudes as thousands of girls living in England and Wales are having their life blighted by this damaging practice."

The World Health Organisation estimates that up to 140 million girls and women have been subjected to FGM, a cultural practice designed to curb female sexuality that involves the partial or whole removal of the outer sexual organs and can cause lifelong physical and psychological complications.

The report states: "A common-held belief in FGM-practising communities is that girls and women who have not undergone FGM have an insatiable sexual appetite, which has to be restrained to prevent bringing dishonour and shame to families."

Measures to protect girls from FGM in the UK have also been announced by police and Border Force agents, who are stepping up operations as the school summer holidays begin.

New Border Force child protection squads are joining with police to target specific flights in a bid to prevent vulnerable girls being taken out of the country for FGM. The beefed-up teams at major airports and border crossings in the UK are on alert for the start of the summer holidays, when experts say girls are at the highest risk of being taken out of the country.

Specially trained Border Force agents will be working with police forces, which are also set to receive new advice stating that officers should put aside cultural sensitivities and fears of being branded racist in order to pursue investigations into FGM. In the first national guidance issued to all police across the country, the College of Policing warns officers not to let fears of being branded a racist stop them investigating FGM.

As the summer holidays start, an 80-strong team of specialist officers at Heathrow, 65 at Gatwick and 21 at Manchester will be on the lookout for at-risk children. The port of Harwich also has a new team, while specialist FGM training is also planned at Birmingham, London City, Stansted, Calais and Dunkirk.

Working with police intelligence, specific flights to countries which practise FGM – including Kenya, Ethiopia, Ghana, Nigeria, Dubai, Egypt and Turkey – will be targeted, said Ingrid Smith, assistant director of the Border Force at Gatwick. "The message we are sending with this intensification of operations is that the practice of FGM will not be tolerated in this country," she said. " Police, Border Force agents and social services will act together to stop this and people attempting to take children out of the country will be caught."

James Brokenshire, the immigration and security minister, said border police were well-placed to gather intelligence on possible perpetrators and prevent FGM from being carried out.

"The school summer holidays are a time of particular risk for many girls," he said. "Which is why we have teams of specially trained officers at major airports with the skills to identify and protect potential victims and stop the perpetrators."

The guidance drawn up by the College of Policing is the first to deal with female genital mutilation and reflects growing public and political concern over the mutilation and the lack of prosecutions of individuals in the UK.

Officers in England and Wales will be told that when investigating the mutilation of young girls in the UK they must consider all child protection measures, including removing a girl from her family if they believe she is at risk of FGM.

Under section 46 of the Children Act 1989 police officers can decide to remove a child who they believe is at risk of "significant harm" to a place of safety for up to 72 hours. They can also apply to a court for an emergency protection order when they believe a child is in imminent danger.

Officers will also be told that they should consider removal of younger sisters in a household where there are concerns that an older girl is at risk of FGM, because the younger siblings will also need protection.

Chief Constable Alex Marshall, chief executive of the College of Policing, said: "We want to ensure that officers have the best information possible to help them to protect the vulnerable and tackle this terrible crime. We must not let perceptions of cultural sensitivities get in the way of action against female genital mutilation.

"This guidance will help build our understanding and confidence in policing this crime so that we're better able to respond to victims' needs and ultimately bring perpetrators to justice."

It warns officers not to be put off pursuing investigations because of the "cultural sensitivities" involved. "Female genital mutilation is the deliberate cutting of the female genitalia. It is illegal, extremely painful and a form of violence against women and girls ... Officers must not avoid tackling FGM for fear of doing or saying the wrong thing or being considered racist."

Female genital mutilation has been illegal in the UK since 1985, and the law was tightened in 2003 to make it an offence for a British resident to travel abroad in order to have FGM carried out on a child. Pressure has been growing on police and prosecutors over the failure – until earlier this year – to bring a single case to the British courts. Alison Saunders, the director of public prosecutions, announced the first ever charge relating to FGM earlier this year but the case has yet to go through the courts.

• This article was amended on 22 July 2014. The original photo illustrating the story was used out of context. It has been replaced.