Dozens of young British women are using social media to boast of joining the Islamic State's terrifying all-female police force – claiming to be doling out savage beatings, punishment lashings, ordering executions and managing brothels where thousands of Yazidi sex slaves are imprisoned and raped daily after being sold for as little as £27. Britons including privately-educated Glaswegian Aqsa Mahmood, 20, and Lewisham-born Khadijah Dare, 22, are understood to have joined the Al-Khansa Brigade in ISIS' Syrian de facto capital Raqqa, helping to patrol the city with guns and daggers hidden beneath their religious robes. The group, which is largely...