The shootings at a civil rights march in Derry, a city also known as Londonderry, hardened anti-British sentiment in Northern Ireland, according to analysts, and led to many fresh recruits for the Irish Republican Army. Three decades of violence
, known as The Troubles, followed. Almost 3,000 people died.
British news organizations, citing security sources, say the man arrested is a former British soldier.
In 2010, the British government released a damning report about the Bloody Sunday massacre
, placing blame overwhelmingly on British soldiers.
There was some provocation by the Irish Republican Army in Derry on that day, but nothing that justified the shootings of civilians, the British government's report found.
British paratroopers had no reason to believe they were under threat from the victims, gave no warnings before firing, and lied to the far-reaching official inquiry into the seminal event, the inquiry concluded.
Only one victim was associated with the IRA, and he was probably not posing a threat when he was fatally shot, the report found.
Members of the British Army fired more than 100 rounds in violation of orders issued to every British soldier serving in Northern Ireland at the time, the report found.
Bloody Sunday has been considered by many as one of the greatest injustices of Northern Ireland's troubled history. Even the name of the city is disputed, with pro-Irish nationalists calling it Derry and pro-British unionists calling it Londonderry.
"Some members of our armed forces acted wrongly ... and for that, on behalf of the government, indeed on behalf of our country, I am deeply sorry," British Prime Minister David Cameron said after the release of the report.