Modern slavery cases involving British children doubled in 2018 as criminal gangs exploit and use more young people to deal drugs, the National Crime Agency (NCA) said on Wednesday.
The number of suspected British child slaves referred to the government last year for support rose to 1,421 - from 676 in 2017 - amid rising concern from police about the growing "county lines" drug trade with gangs using children to sell their wares.
About two-thirds of these cases - 987 - were linked to labour exploitation and believed to be drug trafficking, while the others were mostly related to sexual abuse, according to the annual NCA report on modern slavery referrals to the government.
Overall, about 7,000 possible slavery victims were uncovered in Britain last year - up a third on 2017 - as exclusively revealed by the Thomson Reuters Foundation last month.
Labour exploitation - from men working in car washes to children forced to carry drugs - remained the most common form of slavery, while most suspected victims were from Britain, Albania and Vietnam, the same as in 2017, the data revealed.
"The increase is undoubtedly the result of greater awareness, understanding and reporting of modern slavery," said NCA deputy director Roy McComb, adding that the figures likely only represent a "snapshot" of the scale of slavery in Britain.
"Of particular concern is the increase in referrals made for county lines type exploitation," he said in a statement. "These are vulnerable individuals – often children - who are exploited by criminal gangs for the purposes of drug trafficking."
Thousands of children in Britain are estimated to be used to carry drugs from cities to rural areas - most aged between 15 and 17 - and many are trapped in the growing trade by debt bondage or threats of kidnap, violence and rape, the NCA said.
And victims are getting younger as gangs target children via social media or across schools, foster homes and homeless shelters, according to an NCA report from January.
The number of phone numbers linked to the county lines trade and identified by police has more than tripled over the past year to 2,000 - indicating the scale of the problem, it said.
Despite being hailed as a global leader in the anti-slavery drive, Britain is undergoing a review of its landmark 2015 law amid criticism that it is not being used fully to jail traffickers, drive firms to stop forced labour or help victims.
Britain is home to at least 136,000 modern slaves, according to the Global Slavery Index by rights group Walk Free Foundation - a figure 10 times higher than a government estimate from 2013."Our understanding of the threat is much greater than it was a few years ago, and modern slavery remains a high priority for law enforcement, with around 1,500 criminal investigations currently live in the United Kingdom," McComb added.