Project Guardian is a joint initiative between British Transport Police (BTP), the Metropolitan Police Service ("the Met"), the City of London Police, and Transport for London (TfL), which aims to combat and increase reporting of sexual harassment on public transport in London. The initiative was inspired by a similar operation in Boston, Massachusetts, and began after a TfL survey revealed that 15% of women who used London's public transport had experienced some form of unwanted sexual behaviour, but that the overwhelming majority of incidents were not reported to the police. Project Guardian aimed to increase reporting and reduce instances of such behaviour.