Last year, the BBC's Sam Piranty was given access by the Catalan police, Mossos D'Esquadra, to an investigation into a Nigerian sex-trafficking gang. He spoke to traffickers and women rescued from sexual slavery before filming an early morning raid in November, which led to 23 arrests. He also discovered that the gang is now using London as a gateway into Europe. It's 08:00 in the Catalan Police H