Sarah Montague speaks to Yazidi rights activist Nadia Murad.

When extremists from the so-called Islamic State entered Nadia's village, they killed all the men: six of her brothers were murdered. She and hundreds of other Yazidi women were taken captive and, in the months that followed, they were passed from one group of men to another and gang-raped.

She managed to escape, but it is thought that thousands of women are still being held captive. Nadia Murad was in London to highlight their plight.

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