This July, days after walking into the top job at number 10, Theresa May renewed her commitment to crack down on modern day slavery, describing it as "the great human rights issue of our time". The 2015 Modern Slavery Act gave prosecutors more options to pursue offenders, it handed judges the ability to dole out life sentences and promised more protection for victims. But in the clamour to tackle modern slavery, has the plight of overseas domestic workers, who toil in the homes of wealthy overseas visitors as nannies, cooks and cleaners, been forgotten? This summer File on 4 followed migrant domestic workers as they escaped abusive employers in the dead of night. Through their stories, the programme questions whether recent measures go far enough to adequately protect an invisible workforce who've been tricked and trapped into a life of exploitation. Reporter: Phillip Kemp Producers: Sarah Shebbeare & Ben Robinson.