In mid January 1921 orders were sent to all six battalions of the Mid Clare Brigade asking all available I.R.A. Volunteers to assemble at Parkers house, Belvoir cross on the morning of the 20th of January. The officers of the Mid Clare Brigade had decided to attempt to ambush the R.I.C. patrol travelling from Broadford to Sixmilebridge. An intricate network of roads and junctions offered the R.I.C. patrol a wide choice of routes between the two towns, and the I.R.A. could not be certain that the R.I.C. would travel. To further complicate matters the British forces had become particularly wary of ambushes and often returned to their barracks by a different route to their outward journey. A fair was due to be held in Killkishen on the 20th of January and the I.R.A. were confident they could predict the route chosen by the patrol that day.
On the 20th of January thirty seven I.R.A Volunteers reported for duty in the fading twilight at Parkers house. Half of them carried rifles while the remainder were armed with shotguns and revolvers. A number of the republicans who had arrived unarmed, volunteered as scouts. Michael Brennan inspected his troops, checked their arms and equipment, and began dividing up the men into different sections and explaining the plan of attack. Originally Brennan had decided to attack the R.I.C. patrol in the vicinity of Parker’s house but Joseph Clancy pointed out to him that if the R.I.C. patrol travelled from Sixmilebridge through Killkishen towards Broadford it would bypass the chosen ambush position. Clancy suggested an alternative location for the attack at the rear entrance to Glenwood House. Michael Brennan accepted his advice and at the last moment the I.R.A. column marched to Glenwood occupying their new positions shortly after seven o clock.
At Glenwood the republican scouts were posted along the road a short distance in both directions from the I.R.A.’s new position. The thirty or so remaining I.R.A. Volunteers were dived into three sections under the command of Michael Brennan, his brother Austin Brennan and Tom McGrath. The men in Michael Brennan’s section were all armed with rifles and positioned along a high stone wall just north of the gate to Glenwood house. The stone wall would give then a good cover from enemy fire and a direct line of fire for about fifty or sixty yards. Michael Brennan himself was armed with a revolver and stood a few yards behind the men in his group positioned along this wall. Joseph Clancy was hidden behind a large holly bush on top of the wall keeping watch along the road as the other Volunteers remained hidden. Austin Brennan’s group of Volunteers equipped with rifles and shotguns, was placed fifty yards further north behind another stone wall. The remaining men under Tom Mc Grath’s command were located along the edge of a field a hundred yards to the south of the gate armed with revolvers. The ambushers were to hold their fire, until riflemen under Michael Brennan’s command attacked the lorry.
The intelligence information gathered by Jack Egan showed that the R.I.C. patrol was due to travel through the area at eleven o clock. When there was no sign of the ambush by half eleven one of the republican scouts was dispatched to Killkishen to see if he could get any news of the R.I.C. patrols location. He returned with the report that the patrol had not passed through the village before he began his returned at noon. By half three, the I.R.A. officers at Glenwood came to the conclusion that the R.I.C. patrol had travelled by a different route, and had began to recall their scouts when they reported that a lorry was approaching the ambush position from Killkishen. A few moments later, republican Volunteers waiting in ambush heard the roar of the vehicle’s engine. With a number of the scouts already withdrawn the I.R.A. still did not know whether it was the R.I.C. patrol or not, as a number of civilian lorries had passed during the day. After their long wait the I.R.A. officers were anxious that the column men would not repeat the mistake of the Cratloe and alert the R.I.C. by firing an accidental shot. As the R.I.C. patrol approached Joseph Clancy climbed on top of the wall which Michael Brennan’s section were positioned behind, and kept watch to check if the approaching lorry was the expected R.I.C. patrol. Clancy made repeated appeals to John Ryan and the other riflemen to hold their fire until the lorry came into view and entered the ambush position and then shouted ‘Police’ and dropped down into his position.
As the R.I.C. patrol entered the ambush position the I.R.A.’ still did not know the strength of the enemy patrol and whether there was a second or possibly even a third Crossly Tender lorry following. Because of this uncertainty Michael Brennan did not give the order to fire until the Crossly Tender had almost drawn level with his sections position: “There was no time to get the out posts posted, but as it sounded by only one lorry, it seemed to be a fair chance. … The whistle brought a burst of fire from front and side. My party all aimed at the driver, but though they knocked off his cap and hit nearly everyone else on the lorry, he was unscathed. His steering column was broken though and the lorry went out of control rolling in against the wall where we were standing.” While the R.I.C. Lorry was slowing to a halt Dan Lenehan, threw a Mill’s bomb hand grenade into the back of the Crossly Tender but it failed to explode. As the I.R.A. continued firing on the R.I.C. lorry its driver a Black and Tan named Selve jumped clear across the bonnet of the vehicle and ran for cover throwing aside his belt, revolver, ammunition and great coat in an effort to escape from the I.R.A. Under fire from all three sections Selve managed to leave the roadway and disappeared into Belvoir woods. A second R.I.C. man. Sergeant Egan, who had been seriously wounded left the rear of the Crossly Tender and escaped while the republicans had turned their attention from the lorry onto its fleeing driver.
Within two minutes the ambush ended and Michael Brennan ordered a ceasefire. The I.R.A.’s initial attack had been so effective that the entire R.I.C. patrol been killed or wounded and the troops inside had not been able to return fire. Most of them had been killed instantly, but the other members of the R.I.C. patrol were mortally wounded but had not yet died. They were carried to the roadside and one member of the flying column was sent to Sixmilebridge to summon spiritual aid for them from Fr. Daly and Fr. O Dea. The I.R.A. Volunteers searching the dead and wounded R.I.C. men and Black and Tans recovered eight rifles, seven .45 revolvers, almost a thousand rounds of ammunition. Knowing that the sound of gunfire would have been heard, and reported to the British forces the I.R.A. gathered up the I.R.A. withdrew southwards toward Oatfield after setting fire to the Crossly Tender. Three Black and Tans, Michael Moran from Castlebar in Mayo, Frank Morris from London and William Smith from Kent, had been killed in the ambush alongside two regular R.I.C. men Sergeant Mulloy from Mayo and John Doogue from Laois. The sixth British casualty was the commander of the patrol and the local district inspector D.I. William Clarke from Armagh who had recently been promoted from the Auxiliaries to the regular R.I.C.
As the remainder of the I.R.A. flying column crossed the hills towards the south, they saw the first houses burning as the British forces began another night of terrorism and reprisals in revenge for the ambush. Lorry loads of Black and Tans and R.I.C. from Sixmilebridge and Broadford converged on Killkishen firing their weapons at random in to houses along the roadside as they travelled to the area. After raiding a number of Pubs for drink they began to fire wildly at the inhabitants of the village as they made their way towards Joseph Clancy’s home. When the Black and Tans arrived and found the house empty, they began a ‘police search’ of the house and reduced its entire contents to pieces. By now word of the ambush had reached the Auxiliaries stationed at the Lakeside Hotel in Killaloe, who set off to join in the reprisals at Killkishen. They stopped on their journey to burn the Bridgetown Creamery and various houses along the way. Their next stop was at Cloneconry where they torched Hayes and Ryan’s before continuing on their way stopping at Lissane, Ballykelly, Annaghclare, Belvoir, Knockatureen and Sixmilebridge marking their progress with a trail of burning farmhouses. Upon reaching Kilkishen they set alight a number of farm buildings and haystacks belonging to the Dwyer family. When they eventually arrived in the centre of the village they joined the Black and Tans in looting and burning more houses before they all got so drunk and out of control that their officers had to disarm a number of them that were shooting their rifles and revolvers so freely that they were a danger to themselves and the other members of the R.I.C. By morning the Black and Tans and the Auxiliaries had reduced twenty-one houses to ashes but the British forces reprisals had still not ended. The R.I.C. and Black and Tans returned early the next morning with some British soldiers who assisted them in ransacking houses, burning them and questioning or beating up their occupants.