British Transport Police are appealing for train passengers who helped a victim of sexual assault to come forward.

The incident happened  just after 8.10pm on the 6.40 Middlesbrough to Manchester Piccadilly train service on Saturday,  November 1, as the train travelled between Leeds and Huddersfield.

PC Jo Kellett, leading the investigation, said: “The victim, a 25-year-old woman from Huddersfield, boarded the service at Middlesbrough.

"When the train arrived into Leeds, a man, who has been described as black and wearing an Adidas tracksuit, boarded the train and sat particularly close to her. He then began to whisper in her ear and ask her inappropriate questions.

"He then grabbed her hand and stroked her arm. The victim was extremely frightened and asked the man to move so she could move into the vestibule area. The man followed her.

"The vestibule area was busy and the victim spoke to a number of people telling them what had happened and how she was scared for her safety.

"A woman and two men reassured the victim and stood between her and the suspect. They all left the train at Huddersfield station and waited with the victim until her husband came to pick her up.

“If you were one of the people who helped the victim, please contact us as you may have key information which will assist in this investigation

“Unwanted sexual behaviour of any kind will not be tolerated. The victim, who must have been terrified, did exactly the right thing and showed great courage and strength in alerting other passengers to what must have been a very frightening experience, and reporting the incident to police.”

Anyone with information should contact BTP on 0800 40 50 40 or text 61016, quoting reference MSUB/B12 of 1/10/2014. Information can also be given anonymously to Crimestoppers on  0800 555 111.

In unrelated investigations, police would like to speak to the people pictured in the image gallery below. The people pictured in the images may be witnesses as well as suspects. If you recognise anyone, contact police on 101 quoting the reference number on the image caption.