The ambush was organized by Major General Michael Kilroy, later Commandant of the 4th Western Battalion of the IRA. He and his flying column of volunteers took up position between Widow Sammon’s House and that of Widow McGreal in Carrowkennedy and awaited a Royal Irish Constabulary patrol.
On Thursday 2 June, the West Mayo Flying Column was based in the townland of Claddy, near the road from Westport to Leenane. In the mid-afternoon, O/C Michael Kilroy was informed that an RIC patrol including two Crossley tenders and a Ford car had stopped at Carrowkennedy. The IRA had blocked the road with trenches, which the RIC got local men cutting turf to fill in. Kilroy knew that the patrol would have to return the same way as his men had destroyed Erriff Bridge. The 45-50 men were divided into 3 main sections and subdivided into small units of six men under the command of a more experienced officer. The Westport men, led by Vice-Brigadier Brodie Malone formed one section. They were placed on high ground 120 yards from the road. They were behind a stone wall and removed stones to form firing pisitions. the second section was formed mainly of Newport men. They were positioned further west, from the end of the first sectionsposition along a wood to the main road. The third section, from Louisburgh crossed the road to hold a hill above the junction to Drummin. The sections were to hold fire until all the vehicles were in range of the whole column. Kilroy had learned from the failure at Kilmeena. He handpicked snipers to kill the drivers of both Crossley Tenders. He also assigned men to watch any machine gunners.
On discovering the Erriff Bridge destroyed, the patrol went to Darby Hastings Pub for refreshments. The patrol then headed back towards Westport. The Ford car broke down and was being towed by the second lorry as they drove back through Carrowkennedy. Gus Delahunty, a civilian from Westport, was ordered to drive his own car as part of the patrol. Stevenson, contrary to regulations, was driving the first lorry, when he should have been in the back of the 2nd lorry with his men. This increased his risk and separated him from his men.
At 6.30 p.m. A scout signalled the approach of the patrol. Jimmy O'Flaherty, a former Connaught Ranger, lined up his sights on Stevenson in the lead vehicle. A bullet killed Stevenson through the centre of his forehead. The lorry lurched forward and stopped in the middle of the road and came under heavy fire from above. Police tumbled out quickly and got down behind a bank which gave them some cover. A Lewis gun was thrown out and trained on the third section of IRA men. After two short bursts of fire, the gunner lay dead beside his gun. A second gunner fired a burst of shots from the Lewis in the direction of the third section, then he swung the muzzle in the air to protect himself from the riflemen above, this was unsuccessful and he too fell dead beneath the gun. Three men in all died trying to use the gun, according to Michael Kilroy. 4 men in the lorry were now dead: DI Stevenson and Constables Sydney Blythe, James Brown and John Doherty. The remaining men in the lorry were led by Sergeant Creegan. They attached a grenade launcher to a Lee-Enfield rifle and kept the IRA at bay.
The second lorry was stopped by rifle fire from both sides of the road as soon as shots were heard from the direction of the first lorry, killing the second driver. This lorry coasted to the ditch at the side of the road. After a while the men ran towards McGrale's thatched cottage facing onto the road. They poked rifles through the front windows and through a window high in the gable which looked down on the Westport road. They used up a lot of ammunition unnecessarily and then realized that they had left their spare ammunition in the lorry. They unsuccessfully tried to persuade the Widow McGrale and her young son to fetch the ammunition.
The motor car was some distance behind the second lorry and stopped beyond the cottage. Three men jumped off the exposed side and two remained on the sheltered side of the road which had a thicket beside it next to the cottage. One of the policemen advanced towards the rebel position but was badly wounded.
Two hours went by. Michael Kilroy was worried that if the first lorry did not surrender soon, the column might not have time to concentrate on the police in the McGrale cottage. Enemy reinforcements could arrive from Westport, Castlebar or Ballinrobe, byroad or over the hills to the east. A fresh assault on the lorry was made by Johnny Duffy and Tommy Heavey who had bayonets. A rifle grenade which was being hurled by the police fell back into the lorry and exploded, killing the man who threw it and fatally wounding other police beside him. A handkerchief was hoisted by Sergeant Creegan on a rifle to surrender. Only one of the police in this lorry was unwounded. Sergeant Creegan was fatally wounded in the legs and abdomen. A door borrowed from the Widow Salmon's cottage was used as a stretcher for the badly wounded Creegan. The widow prepared a drink for Creegan and the other wounded constable Cullen who remained outside as it was warm.
The column men captured 22 rifles, 8 drums for the Lewis gun, several boxes of grenades, 21 revolvers, and around 6000 rounds of rifle ammunition. Petrol was shaken from tins over the two lorries and the car and there was a 'furious blaze'.
Eight of the British side were killed outright or died of their wounds and sixteen surrendered. A large number of weapons were seized. The Black and Tans who surrendered were not killed, even though this policy had been endorsed by IRA General Headquarters due to the terror and mayhem they inflicted on civilians. Many of the local people went into hiding to avoid the retribution of the Tans. The IRA volunteers escaped arrest by sheltering in safe houses.
- Price, Dominic The Flame and the Candle
- O'Malley, Ernie. Raids and Rallies (2011 edition)
- RIC Memorial Roll