A day of carnage in Dublin in an increasingly bitter and bloody Irish War of Independence; in total, 31 people were killed. Early in the day, Michael Collins ‘Squad’ and the Dublin Brigade wipes out much of British Intelligence in Dublin. Hours later, British troops take horrible revenge.

In a superbly executed guerilla operation, Michael Collins dispatched his agents to assassinate fourteen British spies (members of the Cairo Gang) in Dublin, effectively crippling the British information system. Not all of those killed were spies or intelligence agents, but it seems all were military personnel.

Collins was a ruthless, unforgiving warrior who wrote of the killings: ‘By their destruction the very air is made sweeter. That should be the future’s judgment on this particular event. For myself, my conscience is clear. There is no crime in detecting and destroying, in war-time, the spy and the informer. They have destroyed without trial. I have paid them back in their own coin.’

The violence did not end there. In an act of revenge that forever stains the British military, a mix of RIC and British Auxiliary forces drove to Croke Park, Dublin where a large crowd was watching Dublin play Tipperary in a football game. The RIC and Auxiliaries fired into the crowd. Fourteen people died, including, Michael Hogan of the Tipperary team.

The violence did not end there. Three IRA men captured on the day (Peadar Clancy, Dick McKee and Conor Clune) were killed that evening while ‘attempting to escape’ Dublin Castle.

Overall the terrible day was a huge morale boost for the Irish independence effort and a disastrous and criminal blunder by the British who only succeeded once again in galvanising Irish opinion even more. It also highlighted the military genius of Michael Collins.