Modern slavery and human trafficking in the UK are more prevalent than ever before.

Police estimate tens of thousands of victims are hidden in towns and cities across the country; many kidnapped then subjected to forced labour or sexual exploitation, often under the threat of violence.

But what happens to victims after they escape or have been rescued?

File on 4 investigates the government system designed to identify and support victims of modern slavery and human trafficking.

File on 4 investigates allegations that a failure to adequately protect victims means some face being drawn back into exploitation by the very gangs from whom they escaped in the first place.

With the Prime Minister describing modern slavery as "the great human-rights issue of our time" is enough being done to tackle the root causes and protect those unable to protect themselves?

Reporter: Paul Kenyon