Police forces face a super-complaint over their alleged failure to protect victims of modern slavery.

Hestia, a charity that specialises in helping victims of slavery, has lodged the complaint today after its investigation found just seven per cent of reported cases of modern slavery were being referred to the Crown Prosecution Service (CPS) by police.

This is despite a 250 per cent rise in the number of operations to more than 1,100, which the National Crime Agency (NCA) last week said had been fuelled by children being exploited by county lines drug gangs.

The super-complaint, which could trigger an inquiry by HM Inspectorate of Constabulary, is being backed by the Victims’ Commissioner Baroness Newlove.

“Victims are being alienated by the criminal justice system to the extent that they disappear or in some cases return to their captors,” said Baroness Newlove.

“Not only is this demoralising but it undermines our fight against this crime. It also seriously undermines our ability to prosecute offenders if we are no longer in touch with the victims.”

Key complaints uncovered by Hestia included victims saying they were not believed by investigating police officers or being treated as criminals when they had been forced to commit crimes by their exploiters.