Police want to trace this man in connection with a sexual assault against a woman on a train in south Bucks.

Between 9pm and 10.30pm on Saturday, May 2, a woman in her 20s was on board the 9.09pm Marylebone to Aylesbury service.

British Transport Police say a man boarded the train at Marylebone and sat next to her, placing a bag on his lap while resting a hand on one of her legs.

During the journey, he engaged in conversation with the woman and made her feel “very uncomfortable”.

He asked for the victim’s phone number more than once, which she refused.

And just before leaving the train at Little Kimble, he hugged and kissed the woman without her permission.

As part of the investigation, officers have viewed CCTV from stations on the route and have found this image of a man they wish to speak to.

PC Hollie Taylor said: “This was a very upsetting incident for this woman, who felt trapped and worried as a result of this man’s actions.

“We treat sexual offences of any nature on the rail network with the utmost seriousness. No one should be made to feel worried for their safety when they travel by train, and we will do everything we can to investigate this incident.”

Anyone with information should contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference M/B10 of 28/05/2015.

Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.