The number of modern slavery cases under police investigation that involve children is "shocking", advocacy group CARE has said.
New figures from the Modern Slavery Police Transformation Programme's annual report reveal a nearly tenfold increase in cases involving children as numbers reached a record high.
The report showed that in the last month, there were 475 police operations into child slavery in the UK, compared with 53 in April 2017.
The vast majority of these children are being exploited by criminal gangs in 'county lines' drug runs for the transportation of drugs across county boundaries. Others are sexually exploited in paedophile rings.
The report warned that the use of children in the drug trade was the fastest growing area of child exploitation in the UK.
CARE's Senior Policy Officer for Human Trafficking, Louise Gleich, said that the increased police proficiency in identifying victims four years on from the introduction of the Modern Slavery Act was partly behind the dramatic increase.
However, she said the figures made it clear that "more still needs to be done" to tackle modern slavery and bring perpetrators to justice.
"This surge in the number of modern slavery investigations involving children is truly shocking," she said.
"It is surely a reminder that the tragic and awful reality of modern slavery here in the UK is all too real.
"The thought of young people being trapped in modern slavery, forced to run county lines transporting drugs for gangs or being sexually exploited is horrendous."
Responding to the report, Iryna Pona, Policy Manager at The Children's Society, said it was important that all people learn how to spot the signs that a child is in danger and "accept that these young people are not troublemakers, but vulnerable children who are being groomed and need help".
"We hear shocking stories of children being groomed with money and drugs before the life of glamour they have been promised quickly descends into a nightmare in which they are stabbed, raped, beaten up and blackmailed," she said.
"They may be too scared to ask for help, however, or may not understand that they are being exploited."
She called on the Government to introduce a missing persons database allowing information about missing children to be shared across police borders.
She continued: "Too many children exploited through county lines are still not being referred to the National Referral Mechanism - the system used to identify victims of modern slavery and human trafficking – and failing to get help from an independent advocate to ensure they are supported as victims.
"Without these changes, more vulnerable children will continue to fall prey to this cynical exploitation."