As soon as the three cars had stopped, their doors were flung open and eight men in balaclavas and hoodies jumped out, leaving their drivers behind the steering wheel, ready for a getaway. From where she was sitting, Katie could see only the third car, the Datsun, but she could see that one of the two men who climbed out of the back seat was carrying a Ruger automatic rifle.

‘Right,’ she said. ‘Five seconds, Francis, and then let’s go.’

Inspector O’Rourke counted down five – four – three – two – one over the radio, and then they all pushed open the doors of their car and scrambled out. On the opposite side of Gerald Griffin Street, the doors of five more unmarked cars were opening up, and the armed support officers came running across the road, dressed from head to foot in black, holding up their Heckler & Koch assault rifles. At the same time, two Garda squad cars appeared at the top of the hill, their headlights on full and their blue lights flashing, blocking off the junction with Cathedral Road, and two more turned into Gerald Griffin Street from Farren Street, approaching The Weavers side by side to prevent the Riordans reversing and trying to escape the way that they had come.

Katie ran through the rain with Detective O’Donovan beside her and Kyna close behind her. She rounded the corner by the Bord Gáis tent just as the last of the armed support unit was entering The Weavers’ front door. She lifted the flap of her raincoat to pull out her pistol and then she followed him inside, through the narrow entrance hall and into the first of the two bars. The bar was dark and smelled of stale beer and furniture polish.

Three of Riordan’s gang were standing in front of the counter, looking bewildered, and a fourth was standing behind it. Five armed support officers were pointing their assault rifles at them and screaming, ‘Don’t move! Drop your weapons and put up your hands! Now!’

Two of the gang were carrying automatic pistols. One dropped his on to the floor with a loud clatter while the other carefully laid his down on a nearby table, on top of a beer mat. The third appeared to be armed only with a baseball bat, which he swung once and then tossed towards the fireplace, knocking over the fire irons.

‘Put up your hands!’ one of the officers shouted at them. ‘And you – behind the bar! Lay down that weapon ye fecking gom – like now!’

The gang member behind the counter was holding up a Ruger semi-automatic rifle. He hesitated for a few seconds and then he started gently to lay it down on top of the bar, two-handed, as if he were offering up a sacrifice. As he did so, though, there was a deafening bang from the next bar, and then another, and then a sharp brrrrp! of sub-machine gun fire.