A 17-year-old girl was sexually assaulted by a stranger on a train to Wandsworth Town last month, according to police.

The girl was waiting at Clapham Junction station when a man tried to speak to her and followed her on to the train.

When she did not respond to him, he sexually assaulted her and shouted abuse until another passenger intervened.

Police were called but the man fled at Wandsworth Town.

Officers are investigating the incident, which occurred just after 2.30pm on Tuesday, June 30, on a South West Trains service to Weybridge.

Detective Constable Sarah Garden said: “I would urge anyone who has any information about this incident, no matter how insignificant it may seem, to contact us.”

A 17-year-old boy from Streatham has been arrested in connection with the incident and has been bailed to return on Friday, August 7.

To report information call the British Transport Police for free on 0800 40 50 40 and quote incident 306, 1 July, or call Crimestoppers anonymously on 0800 55 111.