The United Nations estimates 1.2m children are trafficked across the world each year. In the final part of a series on 21st Century slavery, Lindsay Jennings looks at the victims who disappeared from care in Newcastle - and the trend for trafficking British children.

THEY had applied for asylum the moment they landed at Newcastle Airport, clutching their fake Japanese passports. The three schoolgirls - Mei Fang Weng, 15, Xiu Ming Lin and Yun Jen He, both 16, - were put into the care of social services in Newcastle. Three days later they disappeared and were never heard of again.

Since that case in March 2005, other Chinese girls have arrived at the airport, and vanished in similar circumstances. But rather than running away of their own volition, it is likely they were lured into a life of prostitution - one of the 1.2 million victims of child trafficking across the world.

According to the UK Human Trafficking Centre, in Sheffield, children as young as five from Africa, Asia and eastern Europe are being forced into sexual slavery and pornography or made to beg and steal. They can be found in illegal sweatshops, restaurants and in the food processing industry.

Abandoned children are particularly vulnerable. They often lack education and proper documentation and almost always have no means of support. But many are duped, taken away from their parents by 21st Century Fagins who demand up to £3,000 to give their children better prospects in Britain. The parents believe that their children will be able to send money back home when they start work. But they never hear from them again.

Identifying trafficked children in Britain is one of the key challenges authorities face.

NSPCC director and chief executive, Dame Mary Marsh, says: "These children are incredibly vulnerable; they might be regularly beaten, raped, denied food and basic comforts and have no access to healthcare or an education. Trafficked children are afraid to ask for help for fear of retaliation from their trafficker or being treated as criminals by the UK authorities."

Child trafficking first became an issue in 1995 when social workers in West Sussex found a child had gone missing from care. It soon emerged there was a pattern with young girls from Nigeria being taken to Europe to be used for sex.

Since then, it has been difficult to assess the real scale of the problem. In 2005, a study by the charity Barnardo's found that 12 out of 32 local authorities were aware of cases of young people from abroad who had been sexually exploited. Even though the first sweep of the joint police initiative, Operation Pentameter, was focused on women during brothel raids across the country, at least 12 girls under the age of 18 were rescued, including one 14-year-old.

In the North-East, a report published in March into child trafficking in Newcastle found 16 children were likely to have been trafficked to the region. Of the 16, seven Somali girls, suspected of being brought to the UK for under-age forced marriages, went missing along with six Chinese youngsters, including the three mentioned above.

The research was carried out on behalf of Save The Children and ECPAT UK, a coalition of nine charities, to gauge the scale of the problem outside London. It highlighted a lack of safe accommodation for young people who have been trafficked, and specially trained foster carers to deal with victims. Across the country, it found 80 children had been trafficked and 48 had gone missing from local authority care.

Catherine Fitt, executive director of children's services for Newcastle City Council, says they work closely with Barnardo's and the Children's Society to provide outreach support.

Wendy Shepherd, who runs the Barnardo's Secos project (Sexually Exploited Children on the Streets), in Middlesbrough and is a member of the UK Human Trafficking Centre group, says it's difficult to stop young people disappearing. "If a young person has been brought from abroad to this country they may be groomed to seek asylum once they reach an airport," she says. "They'll tell them 'we'll come and collect you and give you a far better life' but what they don't realise is that they've been tricked. They will appear when people least expect it, send a text message, saying 'meet me around the corner' and that young person will disappear into an abyss."

While Ms Shepherd has yet to work with any trafficked children from abroad in the North-East, disturbingly, she has worked with young British girls who have been trafficked from city to city, known as cross border trafficking. The majority of these youngsters are white, aged from 13 upwards - although she knows of a girl as young as 11- and are lured into sexual exploitation. They can be led into alcohol and drug abuse and some have been given date rape drugs only to awake in strange cities.

Ms Shepherd is aware of children being trafficked into Middlesbrough from other cities and of youngsters being exported from the region. The charity is aware of 76 young people who have been cross border trafficked nationally.

"Generally, a male will have access to a young person, perhaps as a boyfriend or a protector, and before long the young person has been groomed into a position where they are not only having sex with their 'boyfriend' but all his friends too," she says.

"The victims don't necessarily come from deprived backgrounds, but without intervention, they can end up in a life of adult prostitution."

Earlier this year, a study carried out by the Child Exploitation and Online Protection Centre (CEOP) uncovered 330 suspected and confirmed cases of trafficked children in the UK. It revealed a need for better resources on how to identify and protect trafficked children. In response, the children's charity NSPCC launched the country's first advice line last week for people who work with children.

But Ms Shepherd believes the CEOP figure is the tip of the iceberg. "As paedophiles get clever, so will we have to," she says. "It's about sharing intelligence with other agencies if we are going to prevent abuse. Otherwise it could become much more hidden."