At that moment there was a protesting, shuddering groan and the jeep started to slide. Chavasse reached in, grabbed the machine pistol and the stick grenade and jumped back as the vehicle slid over the edge.

It hung there for a moment and then disappeared. There were three terrible, metal-wrenching crashes as it bounced its way down into the valley, and then silence.

Chavasse moved back along the track and peered round the edge of the bluff. The wind was beginning to sweep snow across the steppes in a great curtain, but he could see quite clearly the two jeeps parked on the other side of the bridge and the soldiers moving down on foot to cross the river.

He returned to the others. “It doesn’t look too good. They’re crossing the gorge on foot.”

Katya looked strained and anxious, but Hoffner seemed extraordinarily composed. “What do we do now, Paul?”

“According to the map, we’re only about ten miles from the border,” Chavasse told him. “If we leave the track here and cross over the shoulder of the mountain, we’ll come into the Pangong Tso Pass. About two miles along it, there’s an old Tibetan customs post marked. There may be soldiers there, of course, but we’ll have to risk that.”

“It’s impossible, Paul,” Katya cried, the wind whipping her voice into a scream. “I couldn’t walk a mile in this state. Neither could the doctor.”

He grabbed her arm and urged her up the slope. “We don’t have any choice.”

Hoffner took her other arm and they moved upwards, heads bowed against the driving snow. They paused for a moment in the shelter of some rocks and Hoffner turned suddenly, his face grey.

“My briefcase, Paul. I left it in the jeep.”

Chavasse stared blankly at him and then rage gripped him by the throat, threatening to choke him. Everything he had worked for, all the suffering of the past weeks – all for nothing.

Hoffner grabbed his arm. “It doesn’t matter, Paul. It’s all here in my head, that’s the important thing.”

“That won’t matter a damn if Colonel Li gets his hands on those papers,” Chavasse said. “Don’t you realize that?” He pushed the stick grenade into the old man’s hand. “Here, I know you aren’t much with a gun. If anyone comes at you, just pull out the pin and throw it at them.”

He turned, the machine pistol in his left hand, and slid back down the slope to the track. The slope continued on the other side and he went over without hesitation, glissading down to the wrecked jeep forty feet below, squeezed between great boulders.

He found the briefcase almost at once, wedged under the crumpled driving seat, and he pulled it out and started back up the slope. His heart was pounding and there was blood in his mouth, but he held the briefcase and machine pistol in his left hand and pulled himself up with his right.

He scrambled over the edge of the track and started across. He slipped and fell to one knee and as he got up, he heard voices shouting through the falling snow.

He turned and looked down the track quickly as half a dozen soldiers came round the corner of the bluff, bunched together. He dropped to one knee, braced the machine pistol across his arm and loosed the whole magazine in one continuous burst. He continued across the track and scrambled up the slope, his heart heaving like some hunted animal’s.

He heard the shouts of the men behind him as they started to follow and then the stick grenade he had given Hoffner sailed over his head down to the soldiers and there was an explosion. As it died away, he heard not the sounds of pursuit, but the cries of the wounded and dying.

He had no strength left. For a moment he lay there on his face, and suddenly the snow balled up around him, hiding the valley below.

He scrambled wearily to his feet as hooves clattered over loose stones and a horse moved down the slope to meet him.

The man who sat on its back wore a fur hat, the robe of a snow leopard and soft black boots. A rifle was crooked in one arm.

Chavasse stared helplessly up at him and then the brown, handsome face split into a wide grin.

The snow was a living thing whipped by high wind across the steppes, but down in the hollow between the tall rocks it was strangely quiet.

Chavasse sat with his back to one of the boulders and bared his arm so that Hoffner could give him another injection. Osman Sherif, the Kazakh chieftain, squatted beside him, rifle across his knees, and grinned.

“The ways of Allah are strange, my friend,” he said in Chinese. “It would seem we are fated to make the last stage of our journey together.”

Behind him beside the horses stood his wife, together with Katya. The chieftain’s two young children, heavily muffled in furs, were already mounted, one behind the other.

Chavasse rolled down his sleeve and stood up. “If we don’t get moving soon, we might not even reach the border.”

Osman Sherif looked up through the falling snow at the sky and shook his head. “I think things will get worse before they get better. I had intended making camp here for the night. It is a good place.”

“Not with Chinese troops liable to arrive at any moment,” Chavasse told him.

“But we cannot cross the border before nightfall,” the Kazakh said.

“We don’t need to,” Chavasse said. “If we carry on over the shoulder of the mountain, we come into the Pangong Tso Pass. About two miles from the border, there’s an old Tibetan customs post. It can’t be more than six or seven miles from here. We could rest and cross over later.”

“What if there are Chinese there?”

“That’s a chance we have to take. In any case, there wouldn’t be more than half a dozen of them.” He turned to Hoffner. “What do you think, Doctor?”

“I don’t see that we have any other choice,” Hoffner said.

Osman Sherif shrugged. “It is with Allah. It will mean that we must leave many of our personal possessions behind so that each of you may have a horse.”

“Don’t worry about that,” Chavasse said. “When we reach Kashmir, you’ll be well taken care of. I’ll see to it personally that you’re transported to Turkey to join the rest of your countrymen on the Anatolian Plateau.”

Sudden warmth glowed deep in the Kazakh’s eyes. “You should have mentioned that earlier, my friend.” He slung his rifle over one shoulder and started to unbuckle the load on the first packhorse.

Chavasse moved across to Katya and smiled down at her. “How do you feel?”

She looked alarmingly pale and her eyes had sunk deep into dark sockets. “I’ll be all right, Paul. Don’t worry about me. Are we going to make it?”

He patted her reassuringly on the shoulder. “We’ll make it all right, don’t worry about that,” and then he went and helped the Kazakh with the horses.

When they rode out of the hollow ten minutes later, Osman Sherif was leading the small column and Chavasse bringing up the rear.

The horses sank to their fetlocks in the deep snow and Chavasse rode with his head bowed against the wind, alone with his thoughts. He wasn’t afraid any longer. He was calmly certain that he would survive anything that was to come, even the menace of the man who followed him somewhere back there in the wind and snow.

He started to think about Colonel Li, remembering the endless interrogations and the strange, perverted friendship the other had tried to create between them. The habit he had seized on from the very beginning, for instance, of calling him Paul, as if they were good friends. As if they might conceivably have something in common.

Any possibility of friendship was doomed from the start, of course. It was just another of Li’s psychological tricks that hadn’t worked. And yet the man had seemed almost sincere. That was the most incredible thing about the whole affair.