Taken: Hunting The Sex Traffickers

Channel 4, 9pm

It's extremely grim viewing, but this continuing series following a vast police investigation into sex trafficking provides a vital picture of the horrific reality for thousands of women who are being exploited virtually in plain sight in ‘pop-up' brothels across the country.

A surveillance operation is gradually tightening the noose around seeming kingpin Mark Viner, who officers (right) believe may be responsible for human trafficking. Yet it will still need vast amounts of painstaking work and ingenuity to provide the proof needed to put Viner and his associates behind bars.

Meanwhile, the police check on the trafficked women to ensure their wellbeing: their tales of being raped and forced into prostitution to pay for the upkeep of their children thousands of miles away are just heartbreaking. ★★★★★