Vulnerable young children are increasingly being used by London criminal gangs to make drug deliveries to counties like Kent, the Home Office has been warned.

Nineteen London boroughs have written a letter to the Home Secretary, to say a “national response” to the issue is needed.

They say that they are concerned not enough is being done to respond to the issue.

The letter says there is a "growing concern that the Home Office has not so far taken the action necessary to enable a co-ordinated and consistent approach.”

It states: "We believe that County Lines has the potential to be the next grooming scandal, following the child sexual exploitation scandals we have seen in Rotherham, Oxfordshire and elsewhere in recent years."

It adds: "Just as society treated girls groomed for child sexual exploitation as criminals complicit in their own abuse, we are in danger of repeating this mistake with the vulnerable young people exploited by adults through County Lines.

"As London Boroughs we can take a lead in stopping this phenomenon, but we need national support, otherwise we will always be one step behind the gangs.”

The letter says vulnerable children from London as young as 12 have been found as far afield as Cornwall and South Wales.

Police in Kent have acknowledged the issue of gangs working to extend their activities in nearby counties.

Last year, they set up an operation to target gangs who were using the homes of vulnerable people across Thanet and Canterbury.

A team of detectives based at Margate police station was set up to identify and prosecute the organised criminals who ‘cuckoo’ the homes of others.

Operation Rebuke's aim was to disrupt and deter the gangs who are setting up shop in homes across the district and target young vulnerable children to become drug runners.

Officers say 'cuckooing' is not a new phenomenon and the tactic is on the increase nationally as inner-city gangs look to spread their nets ever wider.