Hassad was forcing him onto the ground, crushing him with his weight. Using his right hand, Porter curled his fist, and smashed it into the man’s jaw. He could tell at once the blow was a good one: he could feel his knuckles crunching into the bone underneath the skin. Hassad reeled back, the pain shooting through him. A smear of blood was trickling away from his lips.

Hassad was preparing to strike back, and even though he’d been unbalanced by the blow, his boot was drawing back, and Porter could see at once he was about to take a kicking. He started to try and scramble to his feet, moving as fast as he could to deflect the impact of the first inevitable blow.

A huge explosion rocked through the mine.

For a second, Porter was too stunned to react. His mind went numb. He could hear the sound of explosives detonating, and the crumbling of rock. How far away? he wondered. The explosion was muffled at first, but the noise was rumbling through the tunnels and rock like a train rumbling through the night.

Christ, he thought. Maybe it’s the Regiment. Maybe they’ve come for us.

Let’s hope to God that’s what it is.

Hassad was looking around desperately, then running for the door. Outside, Porter could hear men screaming, and the din of a rolling series of aftershocks from the first explosion, rattling though the mine like a persistent, steady cough. ‘What the fuck is it?’ he shouted.

‘A bunker-busting missile, I reckon,’ Hassad snarled, his expression grim.

Porter could hear more shouts, and more screams. An ugly smell was drifting under the closed door. It took Porter a moment to recognise it – he had smelt it once before on the battlefield: a mixture of scorched foam and stewed meat, it was the distinctive smell of men burning to death. Christ, he told himself. The place is going up in flames.

If we don’t get out of here, we’re all going to die.

‘Cut her down,’ yelled Porter, gesturing towards Katie.

Hassad was reaching for the door, throwing it open. Outside, the corridor was filled with a thick, noxious smoke, and he instantly slammed it shut again. He looked back at Porter.

‘We need to get her out of here,’ Porter shouted, his voice hoarse. ‘She’s no bloody good to you dead, is she?’

There was no reply. Hassad looked to have been stunned into muteness.

‘If it’s a British attack, and she dies, then we’ve fucking won, haven’t we?’ screamed Porter, handing him a knife.

Snapping back to attention, Hassad took two steps forward. With a swift movement of his hand, he slashed at the ropes that bound Katie to the stake. The knots were strong, and expertly bound, and it took several attempts to free her completely. But then she fell forwards. Porter caught her in his arms. She was so groggy, she was close to losing consciousness, but if they could just get out of here, there was still a chance of saving her.