In the early morning of August 5, 1922, during the Irish Civil War, around 200 anti-Treaty Irish Republican Army (IRA) volunteers are mobilised around Dublin. Their mission is to isolate the city by destroying all bridges and road crossings leading into it, cutting off Free State forces and supplies.

The anti-Treaty IRA, opposed to the Anglo-Irish Treaty and the newly established Irish Free State, aim to dismantle the stone bridges over Dublin’s rivers and canal, lay explosives on road and railway bridges, dig trenches in roads to block movement and scout the surrounding countryside for Free State troops.

They are organised in groups of 5–40, some armed with handguns and grenades, others with explosives and tools like spades and picks. Parties are sighted in the hills south of the city (from Kilakee to Roundwood) and across villages north of Dublin (from Raheny to Blanchardstown).

The Free State’s intelligence service intercepts the plan when Liam Clarke, a captured anti-Treaty officer, reveals the details to Free State Intelligence officers. This intelligence allows the Free State to anticipate and counter the operation.

On August 6, Free State forces move quickly to intercept the IRA. They capture 31 anti-Treaty irregulars at Glencullen Bridge (pictured) and later take 104 fighters in County Dublin, including officer Pat Sweeney. These actions cripple the remnants of the anti-Treaty IRA in Dublin and prevent the city from being isolated.

The “Bridges Job” is a major anti-Treaty attempt to cut off Dublin during the Irish Civil War. Its failure marks a turning point, as Free State forces can now move freely into the city, accelerating the end of the conventional phase of the conflict.