The security forces attempted to arrest more than 400 republicans in a dawn raid. But the intelligence was so poor that more than 100 of those arrested had to be released within days. Many of the new Provisional IRA leadership, including a young Martin McGuinness, escaped.

Three days of serious violence led to 23 deaths but internment stayed in place. As the numbers of those interned increased (reaching more than 900 by 1972), so did the anger among Catholics who believed that many of their own were being needlessly criminalised.