Filmed over 12 months, this three-part observational documentary series tells the story of Britain's biggest police operation against sex trafficking, Operation Pentameter 2, and follows the unfolding investigations and eventual sentencing of some of the UK's most serious sex traffickers. The films follow officers from Bedfordshire, Gloucestershire, Devon and Cornwall as they undertake surveillance operations, mount raids, and break into the extensive criminal networks that traffic women into the UK. The series reveals how the sex trade, fuelled by the thousands of British men who use brothels, reaches far beyond the confines of inner cities, to encompass elegant market towns and quiet suburban streets. 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 Hunt for Britain's Sex Traffickers continues tomorrow and is part of a series of programmes highlighting slavery and trafficking, including drama I Am Slave and Dispatches: Britain's Secret Slaves.