In January 1972, a peaceful civil rights march in Northern Ireland ended in bloodshed. Troops from Britain's 1st Battalion Parachute Regiment opened fire on marchers, leaving 13 dead and 15 wounded. Seven of those killed were teenage boys.

The day became known as 'Bloody Sunday'. The events occurred in broad daylight and in the full glare of the press. Within hours, the British military informed the world that they had won an 'IRA gun battle'.

This became the official narrative for decades until a family-led campaign instigated one of the most complex inquiries in history. In 2010, the victims of Bloody Sunday were fully exonerated when Lord Saville found that the majority of the victims were either shot in the back as they ran away or were helping someone in need. The report made headlines all over the world.

While many buried the trauma of that day, historian and campaigner Juliann Campbell - whose teenage uncle was the first to be killed that day - felt the need to keep recording these interviews, and collecting rare and unpublished accounts, aware of just how precious they were. Fifty years on, in this book, survivors, relatives, eyewitnesses and politicians, shine a light on the events of Bloody Sunday, together, for the first time. As they tell their stories, the tension, confusion and anger build with an awful power.

ON BLOODY SUNDAY unfolds before us an extraordinary human drama, as we experience one of the darkest moments in modern history - and witness the true human cost of conflict.