Proposals to tackle trafficking, outlined by the government ahead of the Modern Slavery Bill have been described as creditable but "modest" by anti-slavery campaigners.
Aiden McQuade, the director of Anti-Slavery International said a lot more work was needed in looking into the issue of domestic servitude - and that the current system of visas for domestic workers "de facto legalises trafficking" for forced domestic servitude.
He said he was not surprised by the estimated numbers released today, and stressed that people are working as slaves in many areas of employment - not just the sex trade.
Analysis from the Home Office suggests as many as 13,000 people may be in slavery in the UK - much higher than previously thought.
Traffickers are using webcams to monitor their victims, controlling their movements ensuring they turned up to work in brothels.
A young woman who was trafficked between gangs of men describes how she was ruthlessly exploited and failed by police.