CCTV images of an alleged train sex attacker have been released by British Transport Police (BTP) after a desperate search of Bradford Interchange by officers proved fruitless.

A 19-year-old woman was left shaken and shocked after the attack on a train travelling between Stalybridge and Leeds on Thursday, August 23 during rush hour.

The victim, from Leeds, was travelling on the 17.11 Manchester Piccadilly to Scarborough service when she was assaulted by the man at 5.30pm. They both disembarked at Leeds where the woman raised the alarm, while the man is thought to have changed on to a Bradford train, which police then tried to intercept.

When they arrived at the Interchange they could not find the alleged attacker, but they are sure he had travelled to Bradford.

The images show the man police want to trace walking with a rucksack on his back.

PC Tahira Bibi, investigating for the BTP said that the victim was very shaken up and distressed.

“The victim was sitting on the train when a man came and sat next to her,” the officer said.

“He then inappropriately touched her then exposed himself.

“This was an extremely distressing experience for the victim, and we are determined to catch the man responsible.

“The man we would like to trace has been described as Asian, 5ft 10ins, approximately 20 years of age and of a slim build.

“He was wearing a short-sleeved red checked shirt and carrying a rucksack.

“We believe that the man may have then travelled on to Bradford.

“If you recognise him, or have any information about this assault we’d like to hear from you, please come forward and speak to us.”

They are also appealing for any witnesses who were on the train as it was a rush hour service. The exact nature of the assault has not been released by police.

Anyone with information is asked to call British Transport Police on 0800 40 50 40 quoting reference B9/NEA 2012 August 30, or call the independent charity, Crimestoppers, in confidence, on 0800 555 111.