POLICE have released a new image of a man they want to trace following a shocking sexual assault as a woman slept on a train.

Officers want to speak to this man after a 23-year-old woman woke to find she was being sexually assaulted on a late night train from London Liverpool Street.

The 12.50am service was heading between Prittlewell and Southend Victoria when the attack happened.

Police hope the new image will see more witnesses come forward.

Detective Constable Paul Cudby, leading the hunt for the attacker, said: "The victim, a 23-year-old woman, boarded the 12.50am service from Liverpool Street to Southend Victoria.

“She fell asleep, but was awoken by a man sexually assaulting her.

“Both the victim and her attacker left the train at Southend Victoria station, and the man left the scene.

“Following an appeal for information in the Southend area, officers are now looking further afield for information.

“We now believe the man boarded a train from Shenfield to Prittlewell before getting onto the train with the woman.

“We are also looking into the possibility he may have made his way to Shenfield from east London.

“We have analysed onboard CCTV footage of the incident and are keen to speak to the man in the pictures.

“I am confident he has key information on this assault.

“This was an extremely frightening experience for the victim and we need to find the person responsible for this assault as soon as possible.”

The attack happened in the early hours of Friday, July 25.

Anyone with information can call British Transport Police on 0800 40 50 40, or text 61016, quoting reference ESUB/B12 of 25/07/2014.

Or you can call Crimestoppers, anonymously, on 0800 555 111.