'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.

'What's happening?' she muttered.

Porter no longer had any idea. When he first heard the explosions he reckoned it must be the Regiment coming in to rescue them, but now he wasn't so sure. They might have used some stun grenades to prepare the way for an assault. Maybe some gas. But this looked like some kind of cruise missile making a direct hit on the mine. Why the hell would you do that? It would risk killing the very people you were meant to be capturing.

Her voice was cracked and weak, but as Porter cradled her in his arms, he could feel some of the strength coming back to her. For the first time in days she believed she might live, and it was amazing what resilience that knowledge could give a person.

'Reckon we can get out of here?' said Porter, glancing at Hassad.

He didn't reply, but the brutal expression on his face suggested he didn't think so. Porter pointed his gun straight at the man, nudging him forward, while holding on to Katie as well. He pulled the door ajar, reeling back as a cloud of thick black smoke hit him straight in the face. He coughed violently, his whole body shaking as his lungs tried to get rid of the air he'd just breathed. 'Corpses,' he whispered, his face drained of all colour.

Porter put Katie onto the ground, and held his breath as he slipped his face around the door, glancing out into the corridor beyond that ran down to the meeting point. It took a moment for his eyes to adjust to the clouds of smoke, and the fumes that were stinging his pupils, but as he focused it was clear that the mine had been turned into a scene of total devastation. The two fighters who normally stood guard against the door had been reduced to a couple of charred skeletons, and there were more corpses as you looked towards the meeting point. A huge fireball, Porter reckoned, must have swept down the corridor, burning everything it met, then, as it sucked all the oxygen out of the space, it would have extinguished itself, leaving behind the heavy clouds of smoke. Only the thick door to Katie's cell had saved them. Even so, to get out they would have to fight their way through the smoke, and the secondary fires and explosions still rippling through the rest of the mine.

Porter tore the shirt from his back. 'Tear this into three strips, then dunk them in water and put one over your mouth,' he barked. 'It's the only chance we've got.'

'You were pointing a gun at my chest five minutes ago,' Hassad growled.

'And you bloody deserved it,' Porter snapped. 'But unless we work together, none of us has a chance of getting out of here alive, so let's just get free of this place, and then carry on our fight later if we have to.'

Throwing the AK-47 he had taken from Hassad across his back, Porter knelt down, and tied the strip of wet cloth across Katie's face. It would help the keep the fumes out of her face. Then he slipped a strip around his own mouth, knotting it tightly around the back of his head. He hoisted Katie into his arms, and headed for the corridor. She was a good-sized woman, at least five eight, and when she was fit would probably have weighed considerably more than she did now. He could feel at once how frail and weak her body had become. Even a fit person would have trouble walking through these fumes, he thought bitterly.

For a weak one, it could be fatal.

'Try not to breathe too deeply,' he muttered.

Porter stepped out into the corridor, pressing Katie's face into his chest to try and keep her mouth away from the smoke. The fumes were so heavy, and the light so poor, it was impossible to see more than a few metres ahead. From somewhere, Porter heard a shout, telling him that not everyone was dead. Not yet anyway. Hassad was already striding towards the meeting point. Porter plunged forward, ignoring the carnage all around him. As he stood alongside Hassad at the centre of the mine, there were at least five bodies strewn across the ground, all of them burnt beyond recognition.

'How the hell do we get out of here?' Porter shouted, though his voice was muffled by the wet cloth strapped across his mouth.

'All the exits are blocked,' said Hassad.

Porter glanced around. The timbers the miners had wedged into place to hold up the roof years ago had been incinerated in the blast. Some were still burning and the roof was starting to sag badly: Porter reckoned it might not be long before the whole thing came down, bringing a couple of hundred tons of rock collapsing onto their heads. The staircase that led down from the lift into the meeting point had been totally destroyed. Flames were still licking upwards where the timber frame of the stairs had once been. It was totally impassable.

'We'll take the back way,' said Hassad.

Along one of the tunnels, Porter could hear an explosion. There was suddenly a blinding flash of light that cut through the fumes and illuminated the meeting point. Porter shielded his face as he felt a blast of heat wash over him. He gripped tighter onto Katie, and tried to follow Hassad. He'd already started marching towards a tunnel, motioning to Porter to follow him. Porter stepped forwards. The fire was gathering pace behind him, and he could hear a scream as it collided with one of the men trying to escape, frying him in an instant. Keeping hold of Katie, he followed Hassad into a narrow channel cut into the rock. There were a couple of bodies at its entrance, but Porter just stepped over them and pressed on. Behind him he could hear the sound of another roof collapsing somewhere, and more screams.

Hassad was twisting his way through a tunnel that was narrowing all the time. The light from the flames licking up around the meeting point had illuminated the first few metres, but it was fading fast, and within a few seconds Porter was struggling to keep track of Hassad through the darkness. A wall loomed up ahead of them, but to the right-hand side, there was a crack that appeared to lead upwards. It was part of an old ventilation shaft that must have been built years ago. 'Here,' said Hassad. 'This will take us to the next level. Where the lift is.'

'The lift won't have survived this carnage,' said Porter.

'There's another exit from there. If we can get through ...'

Hassad started to lever himself up into the hole in the rock. There was enough room for a man to crawl through it just but not enough to carry Katie.

'You push her, I'll pull,' shouted Hassad as he disappeared into the tunnel.

With a heave of his forearms, Porter hoisted Katie up to the mouth of the tunnel. He pushed her into position, ignoring the cry of pain as she smashed her elbow into the rock. 'Just grab his hand,' he shouted, struggling to make his voice heard over the crashing of collapsing timbers behind them.

Porter pushed her again, then pulled himself up into the vertical tunnel. It measured just three feet in diameter: enough space for a person to crawl through, but only just. The surface of the tunnel was pitted and rough, but there were plenty of places to get a grip on the rock. Using the muscles in his legs to propel himself forwards, his arms pushed Katie up. Hassad was dragging her along with his arms. It was hard going but they were making steady progress. Porter could hear a couple more explosions behind him but he reckoned most of the blokes down there must be dead by now. They were lucky just to have made it this far.

They were getting closer. Another ten metres, Porter thought. He could see Katie was using her fingers to try and claw her way to the surface, but she was so desperately weak it was hard for her to summon the strength to propel herself upwards. Hassad was reaching the surface now. He paused, then pulled himself free of the narrow tunnel. Turning round, he held out a strong hand, pulling Katie up, while Porter pushed her from behind, following swiftly in her wake.

They had emerged into a dark cavern that must have once formed a part of the main mine. It was so dark, Porter had no idea how big it was or where it led: the only light was the soft glow sneaking up the tunnel from the fires raging one level below them. 'Where the hell are we?' said Porter.

'One level below the surface,' said Hassad. 'It's a big mine, and we were using only a tiny part of it. These tunnels go on for miles.' He nodded in front of him. 'But to get out we have to go that way.'

Porter picked Katie up again and looked ahead. He could see nothing through the darkness. 'How far?'

'About seven hundred metres along this tunnel, there should be an old emergency exit that will take us up to the surface.'

'You think it's on fire?'

'How the hell should I know?' snapped Hassad.

Porter hoisted Katie onto his back. He was still wondering if Hassad was tricking him, maybe leading him straight into a troop of Hezbollah fighters on the surface. I'll fight that battle when I get to it, he told himself. 'Then we better get moving.'

From down below, another explosion echoed towards them. There were tons of munitions down there, Porter realised, and one by one, the flames were reaching the stockpiles of weaponry, igniting vicious fireballs. The ground beneath them shook, and a pile of dusty debris scattered loose from the ceiling, showering them with fragments of rock and ore. Porter started to pick up the pace, jogging alongside Hassad. As they moved away from the shaft they had climbed up, they lost all contact with the light. Within seconds, they were shrouded in darkness. It was too dangerous to run: they could see nothing, and the path was littered with rocks and pits they could easily trip over. Hassad was hugging the wall, feeling his way forwards with his hands, and Porter was following on behind. The metres were covered painfully slowly. A couple of times Porter could feel himself starting to fall as his feet collided with a rock and a fall might easily finish Katie off in her weakened condition but he just about managed to recapture his balance in time.

Eventually they reached a doorway. A light was shining underneath it: the glow of burning flames. Even standing ten feet from it, Porter could feel an intense heat from the other side. 'It's on fire,' he said, looking towards Hassad. 'There must be another way.'

Hassad shook his head. 'Back there, the mine just goes deeper and deeper underground.'

'It's burning up over there.'

'It's the only way,' Hassad snapped. 'Otherwise, we die down here.'

He took a couple of paces forwards. The exit was made from an old metal fame, with a wooden door inside it. There was a padlock, but it didn't look very strong. Hassad pushed his shoulder against it, then stepped back a couple of metres and charged the door. It snapped free on impact. The padlock broke away, and the rusty hinges collapsed, sending the door crashing to the ground. Porter followed Hassad through. Katie was still clinging to his back, wheezing heavily as a fresh blast of smoke hit them in the face. He was looking into a long thin room, maybe thirty metres deep by five across. A burst of heat hit him in the face. At the far end, he could see the lift that led down to the level below, but it was smashed to pieces and twisted beyond recognition. Flames were licking up from that level, creating the waves of heat that had hit him in the face. Behind the lift shaft, there was a thick, broad channel, reaching down into the mine, and above up to the night sky. Porter reckoned that must have been where the bunker-busting missile came in: its hardened, titanium nose would have pierced the ground, and then bored its way easily through the levels of the mine, before exploding viciously deep underground. Bunker-busters were designed to take out the reinforced concrete layers that protected nuclear or biological weapons: it was no surprise that it had shredded the mine like a carving knife through a sandwich.

Not many countries have access to bunker-busting technology, thought Porter.

But the British do. And the Israelis.

'This way, quick,' yelled Hassad. 'We haven't much time.'

Porter now saw he was pointing towards a corridor that led away from the main room.

Porter glanced around. The area near the lift where they had come in last night was clearly impassable. The missile had left a pile of burning debris. Even the rock looked redhot: touch it and it would set fire to you instantly. The timbers along the room had ignited and burnt, and the floor was now a smouldering mess of ash and embers. There was no way they could cross it. But the corridor Hassad was pointing to looked OK. If I can trust him, thought Porter.

Checking that Katie was secure on his back, Porter started to run across the open space towards the corridor. He could feel great waves of raw heat from the lift, and a couple more explosions rocked through the mine in quick succession. The ash and embers on the floor were burning into his feet: running as fast as he could, he could feel it singeing the soles of his trainers. The ground was vibrating all around him, and the walls were shaking. Another explosion, and then a vicious fountain of sparks shot upwards from the lift shaft like a display of fireworks. This mine can't take much more punishment, Porter reflected grimly. Any moment now, the whole place is going to blow.

Hassad had already turned into the corridor. Porter ran after him. The tunnel was long and thin, twisting up and down through the rock. It was held in place by a series of wooden timbers, many of which were already burning. The heat was searing, like stepping straight into a microwave. Porter could feel the sweat dripping off his skin, and on his back, Katie was coughing viciously, the flannel across her face doing little to control the heavy fumes from the fires all around them.

They covered ten, twenty, then thirty metres. Porter wasn't sure how much more he could take. The temperature was rising all the time. His head was throbbing and his vision was starting to blur: beyond a certain point, he knew that men just dropped from heat exhaustion.

'We can't make it much further,' he shouted to Hassad.

'Just another ten metres.'

Porter pressed on. He could see the tunnel opening up ahead. There was a wooden structure up in front of them, with flames already licking around it, and beyond that a rickety wooden staircase that had not yet caught fire. Behind him, the heat was growing more intense by the second, and he'd already heard the sound of rocks crashing to the ground. As they burnt, the timbers could no longer support the weight of the roof. It was groaning, threatening to collapse at any moment. Ignoring Katie's cough, he pushed on harder, picking up the pace. There might only be seconds left before the whole place collapses, he told himself. Each step could well be the last one.

The wooden entrance was now covered in flames, and for a moment Porter paused. There was no way through, not without risking setting fire to yourself. Already, Hassad had ripped the shirt from his back. He was using it to beat back the flames, creating a space large enough for a single man. 'Take her through,' he shouted. 'I'll follow on behind.'

Porter threw himself past Hassad, and towards the staircase. It stretched up for ten steps or so.

Suddenly he heard a scream.

Hassad.

He was shouting something in Arabic.

Porter looked round.

Part of the wall had come away. Hassad was lying flat on the ground, a heavy timber pinning down his leg and his groin. Flames were licking along the wood, getting closer all the time. He tried to lever himself up so that he could push the timber away, but it was no use. He was trapped, and from the look on his face he knew it. Any moment now, he was going to die.

'Help me,' he shouted.

Porter rested Katie on the staircase. The flames hadn't reached this far yet, but sparks were spitting all over the place, and the heat was intense so it might not be long before the steps went up as well. 'You going to be OK?'

She nodded. 'I ...'

The words ended in another fit of coughing.

'Just stay right there,' said Porter. 'Don't try to move.'

He turned and ran back towards where Hassad was lying on the ground. The timber wasn't that heavy no more than a hundred pounds but it was hot. More than half of it was alight now, and the sparks were spitting into Hassad's leg. Porter grabbed it with both hands, and started to heave it away.

Then he paused. He looked straight at Hassad.

'This is the second time I've saved your life,' he said.

Hassad glanced towards him.

'This time I want something in return,' said Porter. 'You have to help me get Katie out of here, and across the border.'

'Just release me,' shouted Hassad.

The flames were getting closer all the time. A couple of sparks spat on his clothes, singeing his skin. Porter could feel his own face burning up, and his cheeks reddening.

He lowered the burning timber just a fraction, so that it was still pinning Hassad down. 'Give me your word.'

'I'll get her to the border, I swear it,' screamed Hassad.

With a heave of his shoulders, Porter hoisted the timber up into the air, and tossed it clean away from Hassad's legs. He reached down a hand, and grabbed hold of the man, pulling him up to his feet. 'Then let's get the fuck out of here,' he said. 'Before the whole bloody place collapses on top of us.'

TWENTY-THREE.

Their way was blocked by what looked to Porter like no more than an old and rusty manhole cover. Unhooking the AK-47 still strapped to his back, and flipping the gun around, Porter smashed its butt into the disc, pushing it open. His hands grabbed the sides of the hole and he pulled himself up with one swift movement. He glanced anxiously around to see if anyone could see him, but the way was clear. Instantly, he plunged his hands back into the mine. 'Grab hold of these,' he shouted.

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.

Even as he walked, the questions were starting to loop through Porter's mind.

Who the hell fired that missile? The British? The Israelis?

But why?

If they knew where we were, why not just send in a Regiment unit to try and break us out?

Whoever fired that monster must have been reckoning to kill everyone in the mine.

Including us.