A passer-by helped police to detain a man who had escaped with a large amount of drugs following a car chase.

Tac Ops officers were pursuing the Citroen (pictured) through Nelson on Saturday afternoon.

Upon stopping the car, police managed to apprehend the driver but the passenger ran off.

Officers gave chase and was helped by a passer-by who tackled the suspect before police were able to successfully arrest him after finding him to be in possession of a hefty amount of suspected crack cocaine and heroin.

A spokesperson for the police said: "LancsTacOps had a pursuit with this Citroen in Nelson.

"The driver was detained but the passenger ran.

"Following a foot chase the officer was grateful to receive help from a member of the public who tackled the runner.

"He was in possession a large quantity of drugs."