They were solid, trained opponents, noted Porter: they were keeping their discipline, and trying to regroup, but they had been overwhelmed by the speed and scale of the attack.

Porter heard a movement. Up ahead in the corridor, another door was opening. He could see just a sliver of metal emerging through it. Porter recognised it at once. The muzzle of an AK-47. He waited, counting the beats of his heart as he allowed the sniper to expose just enough of himself to waste his own life. An inch, then another inch. It would take just an instant for the man to turn and fire. Porter waited, ticking off one second, then another. The hand was in view. Steadying the M16 cupped into his shoulder, Porter aligned the sights. The man was about thirty, with a slim build, and a scraggy, dirty beard. With a squeeze on the trigger, the bullets exploded from the barrel of the gun. The AK-47 dropped to the ground, as the shards of hot metal turned the hand gripping it into shredded ribbons of torn, bleeding flesh.

With a roar of controlled anger erupting from his lungs, Porter leapt forward, turning the M16 on the wounded man and finishing him off with a rapid burst of fire. Looking up, he could see Kenneth Bratton tied up to a chair that had been nailed to the floor. His arms were bound by rope that was cutting into his bare skin, and a gag had been stuffed into his mouth, and held in place with thick layers of plastic tape. He was wearing a black boiler suit, with staining down the front. In his eyes you could see the look of pure terror: the cringing, pleading fear of a man who knows he is clinging to life by the most slender of threads.

Behind him, there was one more guard. He was a boy, maybe no more than fifteen, with a shaved head and a week of untrimmed beard growing on his face. In his hand, there was a Browning BDA 380 snub-nosed pistol. And it was pointing straight at Porter. For a second, Porter could feel a cold sweat pass across his skin: he thought briefly about Sandy and reflected sadly that maybe he never would get to meet his new baby daughter. He’d had guns pointed at him before. But not with the same lethal certainty that they were intent upon killing him.

‘Easy, mate,’ said Porter.

The boy barked something in Arabic.

There was a hit of nervousness in his voice, Porter noted.

He’s just a kid. He’s bottling it.

Porter stood his ground, pointing his M16 straight at the man, his finger poised on the trigger. He could kill him in an instant. And yet he knew that in the same moment, the Arab could kill him. Or the hostage.

‘Drop the gun,’ snapped Porter.

‘Back, back,’ shouted the Arab.

He was gesturing wildly with the Browning. Porter kept his gun level with the boy’s head. Let him lose his rag, he told himself. Maybe then I can get a clean shot at the bastard.