A teenage girl is fighting for her life in hospital and two other girls are being treated for serious injuries following a crash on the M1.

Police are appealing for witnesses after the incident occurred at junction 5 Northwestern Avenue and Stephenson Way, Watford, at 4.30am on Sunday.

A blue Renault Twingo was parked on the hard shoulder near junction 5 travelling northbound, when a silver 4x4 utility vehicle collided into the back.

A 19-year-old girl from Barnet was trapped in a back seat of the car and is critically ill in St Mary’s Hospital after sustaining serious injuries.

Three other women were travelling in the Twingo. A 19-year-old woman from St Albans and a 19-year-old from Barnet were thrown from the vehicle

The fourth passenger - a 19-year-old woman from Barnet - was not in the car at the time of the collision and was uninjured.

Sergeant Ian Manley from the Road Policing Unit said: “An innocent 19-year-old girl is fighting for her life in hospital and two other young people are being treated for serious injuries.

“We are urgently appealing for any witnesses to the collision or anyone who saw the Twingo or 4x4 utility vehicle prior to the collision to get in touch with us so we can piece together exactly what happened this morning.”

A 28-year-old man has been arrested in connection with the collision and remains in custody pending further enquiries.

All three lanes of the M1 northbound were closed until 10am on Sunday morning.