POLICE are hunting a sex attacker after a 13-year-old girl was molested on a train.

They have appealed for witnesses to come forward, and particularly want to speak to a woman passenger with long purple or red dyed hair who went to the teen’s assistance before leaving the train at Chepstow Station.

British Transport Police (BTP) said the victim was touched inappropriately around 2.30pm on Saturday, February 4, after passing Lydney on the Cheltenham to Maes­teg service.

The girl described her attacker as white, around 30 years old, of medium build, with ginger curly hair.

He was wearing a black baggy jacket, dark tracksuit bottoms and red trainers.

Police would like to speak to anyone who saw what happened or who may have any information which could help with the investigation.

As well as her distinctive hair, the woman who helped the girl is described as white and around 30 years old.

If you have any information, contact BTP on 0800 405040 or text information to 61016, quoting reference number 371 10/3/17.