Children as young as 10 'groomed for sex by gangs'
Children as young as 10 are being sexually exploited by organised gangs of men in cities across the UK, a leading charity says.
Barnardo's says it is working with more than 1,000 children who have been groomed, abused and trafficked for money, and the problem is growing.
It says a specific minister must be given formal responsibility for tackling the issue.
The Department for Education said it was determined to take action.
'Used and abused'
Barnardo's said it had 22 teams across the UK and all but one of them had come across organised child trafficking.
Anne Marie Carrie, Barnardo's new chief executive, told the BBC the problem was far more prevalent than it had previously thought and the 1,000 or so victims identified were "the tip of the iceberg".
She also said the average age of those abused had fallen from 15 to 13 in recent years.
"Children are being passed from man to man, home to home, city to city," she said. "It's the domestic trafficking of children for money.
"This problem is getting worse in that it is getting more organised, certainly the grooming is becoming more organised using technology.
"The children are as young as 10. These children are being used, abused and thrown away by organised gangs of men."
Earlier this month, two married British men of Pakistani origin were jailed in Derby for grooming and abusing several teenage girls. The former home secretary Jack Straw later claimed some Pakistani men believed white girls were "easy meat", but he was immediately criticised for his remarks.
Following the case, the Child Exploitation and Online Protection Centre (Ceop) announced that it had begun a study "to identify any patterns of offending, victimisation or vulnerability".
Ms Carrie said the children at the heart of the issue had "been forgotten as discussion has focused on the ethnicity of perpetrators in high-profile cases".
"Without a minister with overall responsibility the government response is likely to remain inadequate," she added.
A spokeswoman for Department of Education said: "Child sexual exploitation is an appalling crime - it is a form of child sexual abuse and must not be tolerated.
"This is a complex problem and we are determined to tackle it effectively by working collaboratively right across government and with national and local agencies."
Penny Nicholls, director of children and young people at The Children's Society, echoed Ms Carrie's remarks and urged the government to make a single government minister responsible for the issue.
She said: "Too many children and young people are being sexually exploited in the shadows of society, groomed in secret by heartless gangs of sexual predators or bogus boyfriends who shower vulnerable children with gifts and lure them to be horrifically exploited, sometimes for years on end."
Ms Carrie said there were a few typical signs that parents should look out for.
"First of all, that children get gifts they couldn't possibly pay for on their own - they're given mobile phones and various things, they're taken out, they're treated [with] things.
"Secondly, that children begin to be a bit more quiet and secretive about their friends.
"And thirdly, that they have very suspicious sleep-overs. Suddenly, sleep-overs become more prevalent."