Katie was just below him, and had enough of her wits about her to grip on to Porter’s wrists. He pulled her sharply upwards, dragging her out onto the land. Hassad followed on swiftly behind them. ‘What do we do now?’ said Porter, his voice breathless.

‘Run like hell,’ said Hassad. ‘It’s not safe here.’

Porter hardly had time to take in the scene around them. It was still night-time, and visibility was limited. They had emerged about eighty metres from the main entrance to the mine. There was a huge crater in the ground where the missile had smashed into the site, throwing up a ton of hot, molten rock as it cleaved its way through the ground. A few corpses were scattered around the entrance: men who must have been killed when the missile first struck. However, up to a dozen more were still standing, grouped twenty metres behind that, too far away for them to be able to see Porter. Guys who were out on patrol or too far from the missile strike to be killed on the first impact, he reckoned. Probably trying to figure out what the hell has just happened to them.

And whether there is anything they can do for the poor bastards trapped down below.

Porter grabbed hold of Katie, and slung her onto his back. With some food and water and medicine she might be up to walking soon. But not yet. Never mind, Porter decided, as he started to walk steadily forwards. I’ll carry her all the way back to London if I have to. It would be worth it just to see the look on that bastard Collinson’s face.

‘This way,’ hissed Hassad.

He was tabbing across the open ground. The mine was at the centre of a big, open-cast pit, like a moon crater but filled with old and rusting machinery. The banks rose up steeply, taking you back to level ground, but there were pathways and tracks where the trucks must have carried the finished metals they dug here out towards the railways and ports. It was about thirty metres, heavy going with Katie clinging to your back, but they made it. A couple of times, Porter could feel the ground shake beneath him, like the tremors from an earthquake. Some of the soldiers near the entrance a hundred metres behind them were running around, shouting as holes appeared in the ground where the mine was collapsing. One or two men appeared to have made their way out to the surface, but not many. More explosions, Porter reflected grimly, as he listened to the ground cracking beneath his feet. Finishing off whatever poor sods are still down there.

Sweat was pouring off his skin as he marched on. He’d ripped the wet mask off his face: the air up here was clear and fresh, and just getting some oxygen into his lungs was doing him good, but he was half naked, and his body had taken a terrible beating in the past few hours. There were cuts and bruises all over him, and his skin felt charred from the intense heat of the mine. His lungs felt as if he’d just smoked about two million cigarettes, and his head was spinning.