Rail passengers are being encouraged to report sexual offences through a new public awareness campaign launched today.
British Transport Police (BTP) says public information and reports are vital to helping catch and convict offenders.
A victim, speaking for the first time, explained how an offender sat next to them on a busy train and pretended to fall asleep in order to assault them.
Jen, 22, who chose not to reveal her surname, told Sky News the assault on her lasted around 15 minutes.
"I felt really panicked. I really didn't know what to do."
"Within a couple of minutes his hand was sort of resting on my knee," she added. "Just lightly stroking it."
Jen was on a train from Cambridge to London. She filmed part of the assault and shared it with her friends in a group chat.
"As time went on, it progressed further up my thigh. I was getting increasingly more uncomfortable but it was only when it got to the top of my thigh and in between my legs that I thought I have to do something.
"I was still messaging my girls chat and they were obviously like, 'Oh confront him, slap his hand away'. But I was like, I'm not gonna do that. This man is like six foot tall."
Instead, Jen sent a message to BTP and moved carriages. She says she received a response straight away so enlisted help from other passengers to get a description of the offender.
Officers met her at King's Cross station where Jen helped point him out before police arrested him. The man, who cannot be named for legal reasons, pleaded guilty and was sentenced to four years in prison.
Data released at the end of last year revealed over a third of women have been victims of sexual harassment or sexual offences while commuting by train or Underground.
The survey, conducted by BTP, also showed that 51% of those who have been victims of sexual offending say that other passengers tried to help them, yet only one in five people who have witnessed sexual harassment have reported it to police.
BTP says its Your Piece of the Puzzle campaign will help offenders get caught and convicted.
Temporary assistant chief constable Paul Furnell said:
"Every piece of information we receive, whether it's from a victim themselves or from a bystander can play a part in a wider investigation against an individual.
"They may have made a sexual remark to you on the train, but the day before they could have sexually assaulted someone else.
"Your information may be the missing piece which leads us to identify the offender and secure justice for all their victims."
He added:
"We know these crimes often go under-reported for various reasons. Victims tell us they doubt themselves, or that they feel that what happened to them was minor and reporting wouldn't be worthwhile.
"With this campaign, we want to highlight that this couldn't be further from the truth.
"We have dedicated task forces and specialist teams to detect and investigate and we leave no stone unturned in bringing offenders to justice, but we need the public to make sure they are reporting all instances to us so that we can identify offenders fast and get them off our network."
(c) Sky News 2024: 'I felt panicked': Police target sexual harassment and assault on trains