A man who sexually assaulted two women on board a train was chased down the tracks after forcing open the doors to escape.

Concerned passengers raised the alarm with staff after the man inappropriately touched a 21-year-old woman while her boyfriend was in the toilet, and a 19-year-old as he sat opposite her and her boyfriend minutes later.

The second victim’s boyfriend was slapped in the face when he told the man to stop, before forcing open a train door and fleeing along the tracks after a staff member had pulled the emergency cord.

Police have released CCTV images of a man they would like to identify in connection with the incidents, who boarded the Victoria-bound train from South Croydon on February 28.

Detective Constable Andy Parkinson from the British Transport Police said: “This was a frightening and intimidating experience for both victims and this sort of behaviour is completely unacceptable.”

Anyone with information about the incident, which happened near Clapham Junction at about 9.36pm, can call the BTP free on 0800 405 040, quoting reference 476 of 28/02/10, or Crimestoppers anonymously on 0800 555 111.