Devon and Cornwall Police is urging people to recognise the signs of county lines exploitation as part of a new campaign aimed at breaking the silence around child criminal exploitation.

The force is supporting the national Crimestoppers campaign "Missing, controlled and exploited: the hidden reality of county lines in the UK", which highlights how organised criminal gangs groom, control and manipulate children and vulnerable adults for profit.

County lines activity is often associated with drugs, but police say it is also a form of exploitation where young people can be forced into transporting drugs, carrying weapons and travelling long distances under threats, intimidation or violence.

The campaign encourages people to share information while reassuring them that reports made through Crimestoppers can remain completely anonymous.

Detective Inspector Steve Moorcroft, from Devon and Cornwall Police, said county lines continued to affect communities across the UK, but much of the activity remained hidden.

"The importance of reports from the public to help us see the extent of criminal activity, and where it's happening, cannot be overemphasised, but we understand why crime often goes unreported," he said.

"People are unsure what they have seen, and they fear being wrong about it. They may also worry about getting involved.

"This is why people should be assured that if they would rather not speak to the police, they can make a report through Crimestoppers and remain 100 per cent anonymous."

Police say warning signs of exploitation can include children repeatedly going missing, changes in behaviour, associating with unfamiliar adults or groups, carrying weapons, having more than one phone, or suddenly having expensive clothing or possessions.

DI Moorcroft said children involved in criminal activity may actually be victims of exploitation.

"Information received from the public is vital to the police in understanding where the exploitation of children is taking place and who is involved," he said.

"Intelligence received from the public plays a very big part in the success of this work," he added.

You can report a crime anonymously to Crimestoppers on 0800 555 111 or make a report online.