County Lines involves gangs from urban areas who exploit children to set up drug distribution networks to rural areas, market towns and coastal areas.
Gangs and drug dealers often use violence and intimidation to set up and maintain such networks. This also includes forcing vulnerable people from their homes to set up drug dealing bases, a practice known as "cuckooing". The most recent national assessment of County Lines, by the National Crime Agency, suggests there are more than 1,000 such networks in operation.
Read more on the Dorset Police website.