I didn't say anything. I'd thought about that before but it hadn't got me anywhere, simply confirmed that we had a private cell dogging my shadow, infiltrating Bamboo, driving me to ground.

'I'll have to signal,' Pepperidge said, 'of course.' The line cracked, and I waited. Chong came through the gates, standing inside, his back to me, stamping his feet, gloved hands rammed into the pockets of his coat. An engine was rumbling and I watched the gates; they were heavy timber, with gaps at the hinged ends, a gap in the middle. 'I will relay,' Pepperidge's voice came again, 'what you've told me. They'll want to know what your plans are.'

That had been the reason for the silence on the line: he'd been thinking out how to put it, because this was going to be rough.

In a moment I said, 'To find the subject?'

It was an army vehicle, a camouflaged personnel carrier; I watched it through the gaps in the gates, past Cheng's motionless figure. It was loaded, the carrier, Chinese troops in battle dress. It was going slowly, toward the centre of the city.

'Yes,' Pepperidge said, 'your plans are to find the subject, of course. But London will ask for details.'

Either they were coming down from the intersections in the north, the roadblocks, or they were moving into the town from an outlying base, to begin a house-to-house search for Xingyu Baibing.

'Tell London they can't have any details,' I said into the phone.

The carrier had stopped, not far from the big green Jeifang, and Chong turned and stood facing me now, his mouth working on the chewing gum, his eyes blanked off. We'd agreed, on our way south through the night, that we would go on using the truck as our base, at least for the first hour or two of theday, that it wasn't a risk, wouldn't call attention. There were hundreds of these things in the city and around it and along the roads to Chengdu, Golmud, Kathmandu, most of them painted green like this one. The only man who could have recognized it as ours was dead.

But perhaps we were wrong, because boots were hitting the ground as men dropped from the carrier. Or their citywide search was going to start here, at the truck depot.

'It's like this, you see' — Pepperidge — 'I've got every confidence in you, and I think you've got as good a chance as anyone of bringing this thing home.'

The mission. As good a chance of bringing it home as any other executive they might fly out here to take over and do what he could to go in cold and try pulling something else out of the wreckage.

'The only point,' I said, 'in getting someone else out here would be that he could work at street level.' Unknown to the police and the PSB, unknown to the private cell.

Boots on the outside. I watched the gates. The engine on the personnel carrier was still running; it hadn't moved on.

'What they'll say' — Pepperidge — 'is that while I have total confidence in you, they cannot share it. Unless you can give me any idea of where you plan to go from here, they may well instruct me to send you out of the field.'

He hadn't liked saying that. He would have done anything not to say it.

'I quite understand.'

Best I could do, put him out of his misery, take it like a man, so forth, as I watched the gates and saw coming over to them, three soldiers.

Chong didn't move. He was standing twenty feet away between me and the gates, facing them now, perfectly still. There were trucks standing in the depot, a dozen or more, most of them big Jeifangs, adequate cover.

On the far side was a low wall, and that was the way I would have to go. And this is the problem of going to ground: you can be forced at any minute to run, and keep on running. There's no base anymore that you can work from, no stability; the sands are shifting all the time under your feet.

You can see their point, can't you, in London, quite understand.

Shivering in the first pale light of the new day, shivering under the warm padded coat, the one I'd taken from the man in the temple, first his life and then his coat, uncivil of me, I will admit, shivering despite its warmth as the soldiers came to the gates and started banging on them.

'Da kai!'

Chong didn't move, shouted back at them — 'Zher hai mei ren.'

Pepperidge: 'I can only obey their instructions, of course.' London's. 'If they-' he broke off, 'was that someone shouting?'

'Yes.'

'Are you pressed?'

'Not really.'

'Tamen shenme shihou dao?'

Crackling on the line. 'Who is shouting?'

'Chong. He's all right, but I might have to ring off. If I do, I'll get through to you again from somewhere else.'

In a moment, 'Don't leave anything too late.'

Chong hadn't moved. 'Jiu dian!' Shouting at them.

He would give me time, I knew that. If they started forcing the gates he'd turn and give me the signal and we'd separate, make our own way out, if they didn't start shooting first.

'Look,' I said, 'they can't get him out of Lhasa. He's still here somewhere. I'm going to find him.'

Soldiers banging at the gates.

Chong standing perfectly still, shouting at them.

'Lihai zher ba. Jiu dian huilai!'

Pepperidge on the line, worried by the noise. 'I'd be happier if you'd ring off and look after things there.'

'He's still in this town,' I said, 'and I'm going to find him. Tell them to give me a bit more time. A few hours.'

Banging at the gates.

'That's all I'm asking. A few hours.'

Chong hit the brakes and the big truck lurched to a stop.

'What did you tell them?'

'Jesus,' he said, 'we've done a kilometre in thirty minutes down this goddam road.' We were blocked off by a yak wagon, couldn't overtake. 'I told them nobody was at the depot yet, they'd have to come back.'

'They didn't argue?'

He rested his hand on the huge vibrating gear lever, the engine rumbling. 'Sure they argued. But their heads are full of rice.'

One of the yaks was lying slumped in the shafts. 'What's the problem?'

'It's died. Everything dies, wait long enough.' He kicked the clutch and hit the gear lever and we moved off again. 'We going anywhere?' He was still furious, his throat tight when he spoke. 'We going to find where they took him, maybe?'

I watched the road ahead.

'Eventually.'

This was the road south into the town, Linkuo Lu, where the temple was, where I'd taken the coat from the man. Grit blew in through the cracks of the doors; there was a wind getting up. Eventually, yes, of course, we would find where they'd taken Dr Xingyu Baibing, and we would bring him back under our protection, but meanwhile they would not be very happy in London, there would be no dancing in the streets.

Subject seized, location unknown. PLA sergeant deceased.

Croder at the signals board, his black basilisk eyes watching the man with the piece of chalk as the stuff came in from Pepperidge, Hyde standing there poking his tongue in his cheek, the whole place very quiet as they listened to his voice, the calm and gentle voice of my director in the field as it reached them through the government communications mast in Cheltenham and the unscrambler in Codes and Cyphers three floors above.

Subject is expected to reveal critical information with or without duress. His captors believed to be private cell, repeat, private cell operating in the field.

There's a bell, in Lloyd's of London, the Lutine bell, since that is the name of the vessel it was salvaged from, and they ring it whenever news comes that a ship has gone down, and there is a silence afterward. It's rather like that in the Signals room, when news comes of the kind that Pepperidge had given them now, that the mission had foundered.