A new scheme in London is tackling unwanted sexual behaviour on public transport.

Armed with 120 plain-clothes officers patrolling London's various modes of transport from 7am to 11pm, Project Guardian has led to the arrests of 15 people over the last two weeks alone.

The new zero tolerance approach to sexual harassment came about after a survey found that around 15 percent of women and girls have experienced unwanted sexual behaviour on London's trains, tubes and buses, but about 90 percent of victims did not report it to police.

In a bid to encourage people to share and report any incidents, British Transport Police recently collaborated with Everyday Sexism on Twitter chats that saw victims use the hashtag #ProjGuardian to tell the stories of what had happened to them.

TfL says that between 1 April and 31 August there was a 32 percent increase in the detection of sexual offences, and since the launch of Project Guardian in July, a 20 per cent increase in the reporting of sexual offences, compared to the same period last year.

A safe place for women?