The brothel, in Harrow, north-west London, was raided a few weeks after she arrived. She was arrested, but she did not reveal the full details of her enslavement to the police because the Kosovan Albanian man who had bought her told her that her family would be in danger if she said anything.

Because officials did not realise Katya had been intimidated by her trafficker, they allowed him to visit her nine times when she was in detention, visits he used to intimidate her further.

Katya’s story: trafficked to the UK, sent home to torture (April 19)