Since police resources allocated to trafficking are small, many of the young victims smuggled into the UK each year remain unknown.
Hundreds of children who have been trafficked into the UK are disappearing each year from the care system, amid allegations that government and local authorities are failing to protect them.
The Child Exploitation and Online Protection Centre, a government agency, estimates that at least 300 juveniles identified as trafficked have disappeared from local authority care over the past three years.
Collated figures from the NSPCC yesterday showed they had dealt with 549 trafficked children in the past three-and-a-half years, although there was no indication of how many had since disappeared after being delivered into care.
Charities have urged the government to adopt a scheme successfully piloted in Scotland, in which guardians are appointed to act as advocates and points of contact for all children believed to have been trafficked. The government has so far rejected proposals to extend the scheme to England. "Guardianship is an essential cost-effective way to prevent children from going missing from care," said Christine Beddoe, director ofchild protection charity Ecpat UK.
"It would ensure that victims of child trafficking now in care have access to the safe housing, education and legal support which would prevent them slipping back into the hands of their exploiters."
A policy document by the Conservatives in 2008 estimated that "over half of trafficked children disappear from social services". The document also criticised the absence of "safe accommodation" providing 24-hour care for trafficked children. But concern is growing that the party has little appetite to tackle the issue now it is in power.
Home Office sources have suggested that a forthcoming strategy paper on human trafficking is unlikely to include a specific section on child trafficking, an omission that will infuriate campaigners. "We have worked tirelessly with government officials over the past five years to develop a national action plan and a robust protection framework for child victims of trafficking," said Beddoe.
"To see this washed away almost overnight is a scandal. It's as if the Home Office have shredded all the facts and figures."
The government has a statutory duty to provide care to children regardless of nationality or immigration status.
New figures released by the children's charity NSPCC show that during the year to April its child trafficking helpline dealt with 146 cases alone, although experts say this is merely a fragment of the true picture.
Scotland Yard will launch a freephone trafficking hotline to encourage victims to come forward in response to concern that the scale of thecrime remains largely unknown.
Detective Inspector Gordon Valentine, the former head of Operation Paladin, Scotland Yard's specialist anti child-trafficking team of police and UK Border Agency officials, said yesterday that the issue did not seem to be a priority for policymakers.
Valentine, who retired on Friday, said that although the Yard had made progress in identifying child victims, there was a concern that the team – which has just five officials – needed to be expanded if traffickers were to be dissuaded from targeting the UK. He added: "Paladin has been a real success and should be expanded, but one issue is that it sits between two stools, the UK Border Agency and the police, and there is an issue about who's going to drive it. The Met are fully committed to Paladin: it's just [a matter of] convincing the wider authorities. Logically, [tackling child trafficking] is cost-effective, but because you can't put costings to it, it's difficult to sell [to policymakers]."
Anne Marie Carrie, Barnardo's chief executive said: "It is imperative that we identify these children quickly and accurately. Failure to do so means they are left without the help and support they so urgently need."
Anthony Steen, former Conservative MP and head of the UK's Human Trafficking Foundation, said: "Child trafficking remains unseen and children don't complain or answer back."
The Home Office said it took the issue extremely seriously and that it remained "core" police business.