The driver of a bus which crashed in Croydon yesterday, injuring 20 people, has been arrested for drug driving.

Eighteen people were taken to hospital after a route 198 double-decker crashed on Station Road, Croydon, at 12.20pm on Sunday.

It collided with another bus, a car and a bus shelter at West Croydon Bus Station in south London, Scotland Yard believes.

Metropolitan Police officers arrested the driver, in his 60's, on suspicion of driving under the influence of drugs after failing a roadside drugs screening test.

He has since been released.

A 15-year-old passenger was taken to a south London hospital where she remains in a critical condition.

Steve Reed, Labour & Co-op MP for Croydon North, tweeted: "Hope and pray the young woman hit by a bus and others affected at Croydon bus station will be ok - horrific incident requires full investigation into how this could happen."

Twenty patients were treated at the scene and 18 were taken to hospital with mostly minor injuries, the London Ambulance Service said.

Eight ambulance crews, a motorcycle paramedic and London's Air Ambulance were also in attendance.

Anyone with information is asked to contact the Metropolitan Police on 101.