A week-long police operation to target sex offences carried out on tubes, trains and buses saw 13 people arrested.

These included a man held for outraging public decency by taking pictures up a woman’s skirt at Gunnersbury tube station, while another man was also arrested for the same charge but at Green Park.

Project Guardian, run by the British Transport Police, took place last Monday (14) until Friday (18) and had the support of the Metropolitan Police Safer Transport Command (STC), City of London Police and Transport for London (TfL).

During the week of action, hundreds of uniformed officers were on patrol giving advice to commuters about reporting any sexual harassment they experience while on public transport while plain clothes officers were deployed to identify any suspicious behaviour across the network.

Other incidents included a man bailed for sexual assault at Hyde Park Corner; and two others arrested and bailed for sexual assaults at Green Park.

In the 15 months since Project Guardian was launched, there has been a 31 per cent increase in the reporting of sexual offences - up from 360 in Jan 12-Mar 13 to 455 in April 13-June 14.

Around 2,000 police officers and PCSOs working on London’s transport system have now been specially trained to deal with these types of cases, which has led to a 26 per cent increase in the detection of sexual offences.

Chief Superintendent Paul Brogden, of BTP, said: “Our message is clear – we want passengers to feel confident on their journey and to know exactly where to turn when they need help.

“A lot of victims do not report their experiences to us, for a number of reasons. Some worry that they won’t be taken seriously, or there is little that can be done to stop sexual crime, but this is not the case – you don’t have to suffer in silence.

“We will always be there to listen and will do everything we can to find those responsible. “Unwanted sexual behaviour on the transport network is completely unacceptable and we will do everything we can to support you and bring offenders to justice.”

Siwan Hayward, TfL’s Deputy Director of Enforcement and On-Street Operations, added: “We care about our passengers and every journey they make and will not tolerate unwanted sexual behaviour of any kind on our transport network.

“If someone has made you feel uncomfortable, for example, touches you in an inappropriate manner, please tell the police or a member of our staff. They can then not only target the perpetrator, but also help to prevent it happening to someone else.”

To report any incident of a sexual nature which to British Transport Police call 0800 40 50 40 or text 61016 with details of what happened.

For an incident that has occurred away from the railway network, call 101. In an emergency always dial 999.