More than 200 shipping containers are being searched and four people have been arrested in dawn raids on a suspected county lines drugs gang.

Officers from the Metropolitan, Essex and British Transport Police joined for the operation on Wednesday, focusing on a commercial container yard in Purfleet, Essex.

It is believed the gang used the site for storage, with investigators discovering drugs, cash, weapons and three stolen off-road vehicles in the first few hours of searching.

Police say the suspected gang operated in London and Lincolnshire.

County lines networks are urban drug dealers that sell illegal substances to a rural customer base and are notorious for exploiting children to act as couriers and taking over the homes of vulnerable people.

Detective Sergeant Owen Morgan, from the Metropolitan Police, said: “There’s an undeniable link between drugs and violence, and it’s crucial we continue to act on this.

“That’s why disrupting the supply of drugs continues to form a central part of our work to tackle violence on the street.

“This operation will not only disrupt criminals using lock-up facilities to store their criminal property, but will also supply a wealth of information that, following this operation, will be fully investigated.”

The four people arrested were one man detained at the yard on suspicion of possession of a firearm while three others – two men and a woman – were arrested for suspected drugs possession during connected raids on homes in Havering, east London.