In 2012 an Indian student was violently raped on a moving bus in Delhi and died of horrific internal injuries. Leslee Udwin spoke to one of the rapists on death row while spending two years making a film about the case. She came away shocked by India's treatment of women - but inspired by those seeking change.
The horrifying details of the rape had led me to expect deranged monsters. Psychopaths. The truth was far more chilling. These were ordinary, apparently normal and certainly unremarkable men.
On 16 December 2012, the 23-year-old woman had been to see a film, the Life of Pi, with a male friend. At 8.30pm they boarded an off-duty bus, with six men on board, five adults and a juvenile. The men beat the friend and each raped the woman in turn, before assaulting her viciously with an iron instrument.
Mukesh Singh, the driver of the bus, described to me every detail of what happened during and after the incident. While prosecutors say the men took turns to drive the bus, and all took part in the rape, Singh says he stayed at the wheel throughout.