In 2007 the government tasked Britain's 55 police forces to tackle the trafficking of women into the country for sex.
This first programme documents the initial stage of the operation, in which the police raid brothels across the UK and use victims' testimonies to garner intelligence about the criminal networks that run them.
The film follows Detective Constable Andy Leigh as he gathers evidence through covert filming, information from local estate agents and liaison with other forces to build a picture of what's happening across the nation.
All brothels under surveillance are raided at the same time to maximise the amount of evidence from victims, customers and the brothel managers. What emerges is a tale of innocent women, brought and sold into sexual slavery.
The evidence enables the police to take their first steps up the ladder from the brothel managers to the criminal masterminds responsible for the illicit trade.
