“Drug supply is not new, however the exploitation of vulnerable young people by criminal networks, to move and supply drugs across the country, takes this offending to a new level,” said Tim Champion, a detective superintendent.

“The use of the Modern Slavery Act is a proportionate and necessary response,” he said in a statement.

Senior police officials and Britain’s anti-slavery tsar Kevin Hyland last week told the Thomson Reuters Foundation that using the law to prosecute those who exploit, traffic and enslave people would send a strong message to other criminals.