The Guardian view on the Bloody Sunday anniversary: the legacy remains | Editorial

Even 50 years later, the killings in Derry in 1972 cast a long shadow over Britain's policies in Northern Ireland

For many on both sides of the Irish Sea, the killing of 14 unarmed civil rights demonstrators by members of the British army's Parachute Regiment on Bloody Sunday in 1972 remains the defining outrage of Northern Ireland's 30-year Troubles. It was certainly the most politically damaging to Britain. The shootings, which took place in Derry's Bogside district 50 years ago on Sunday, shocked these islands and the world. They still do and they still should. Bloody Sunday was not the only senseless act of violence during the Troubles. Many more killings were carried out during those 30 years by paramilitary groups from both sides than by the security forces (and more than five times as many in the case of the IRA). But the shootings in Derry made the Northern Ireland crisis deepen dramatically, led to a steep escalation of violence, caused a boost in IRA recruitment and did huge reputational harm to Britain, its Northern Ireland policy and its institutions.

Almost as bad as Bloody Sunday itself was the official attempt to cover up what happened, and the lies that were consistently told, including at the highest level of government and in the first judicial inquiry that was announced days after the killings. In the end it would take nearly 40 years before the UK government acknowledged the truth about 30 January 1972 and apologised, after Lord Saville's inquiry found in 2010 that none of the casualties were posing a threat or doing anything that would justify shooting them. Even now, many aspects of Bloody Sunday remain sources of dispute, in particular the failure to pursue individual soldiers through prosecutions.