Seeing to Xingyu, oh for Christ's sake who's been bitching about the use of precious euphemisms, killing him, yes, killing Xingyu, I take your point.

'You didn't draw a gun,' Pepperidge asked me, 'this time out?'

'I never do.'

We're given one or two options on our way through Clearance, draw a weapon if we feel like it, draw a capsule; but I don't like guns; the hands are quieter and I prefer going in close.

'I know,' Pepperidge said, 'but I just wondered, you know, this time. In the kind of situation we're talking about you might not get a chance of staying near him, near enough. Question of distance, timing, chance of pulling off a shot.'

My hands had gone cold around the mug, the tea was cold, my spirit was cold, and I got off the bed and put the thing down on the chest of drawers and told him, 'You can't insist. You cannot insist.'

Touching my arm, 'Of course not. I've just got to sound you out, you see, find some sort of compromise. Got to remember, though, haven't we, that there's rather more at stake than the disinclination of one single executive to take a life. There's the future, isn't there, of China and Hong Kong.'

Beginning to feel light-headed, you've got to avoid stress, the guide had told us, or you'll make things worse, the altitude sickness, take it easy, walking. I was walking about now, Pepperidge moving over the wall to give me room, that bloody cockroach crawling across the wainscoting, looking for a way out, felt like, I felt like putting my foot on the thing, Ferris would have done that, he's always looking for beetles to tread on, makes me sick because where do you stop, putting my foot on a cockroach, on Xingyu, said, I said- 'They must have provided for an accident, in their original planning in London, an accident to Xingyu, I mean they-'

'Oh yes.' His voice gentle, reasonable. He knew I was looking for a way out and he wasn't going to let me have one. He couldn't. 'There are several known dissidents in Beijing available, top intellectuals much admired by the people. London would certainly have gone to one of them, through the embassy, and put things to him.'

'You think someone's been briefed to take Xingyu's place, if he gets killed?'

'We can be certain. Most of the planning was made by Bureau One, with Sojourner as his adviser. But we don't want to see Dr Xingyu as in any way… expendable. We would hope, if anything happened to him, that his replacement could rally the people under the protection of the tanks; but we are certain that Dr Xingyu could do it. He is our highest priority. But if there were any risk of his exposing the mission…'

Walking about, I walked about, cold all over now, deathly cold, logical thought not coming easily but it didn't take a lot of working out, Xingyu Baibing was the messiah, with the future of all those people in his hands, but also with a bomb in his head they were asking me to detonate if he became a danger to them.

Pepperidge, watching me, the naked bulb in the ceiling reflected in his yellow eyes, waiting for me to understand that I hadn't got a chance. The objective for Bamboo was to protect Xingyu Baibing, but that objective would automatically be overidden — if something went wrong — by the highest priority of all: to protect the mission itself.

This hadn't been part of the planning, specifically; it had been built into the very bones of the Bureau in its conception, a commandment carved in stone: Protect the mission.

In the end I said, 'No gun.'

'Very well.' He had to accept that much and he knew it. I've got my commandments too. 'But you accept the need to avoid any risk to the mission?'

Said yes.

I had said yes.

Lying here in the padded sleeping bag with the dust settling onto my face, making it itch, lying not far from him, from the messiah, watchful guardian and defender of his fate, but if things went wrong, the means implement of his crucifixion.

Blood on the floor.

I was sitting against the wall on a slatted bench, head down, chin on my hands, looking across at the counter some times and then looking down, ill, depressed, abandoned to my fate, appropriate cover for a place like this.

Streaks of blood across the floor, he'd been brought in a minute ago, a young Khampa horseman, I would have said, in his brigand's garb, they ride as if into the teeth of hell and sometimes come a cropper. A woman in a stained white smock came with a mop and bucket, shaking her motherly head. There were a dozen people in here, most of them at the counter, some with an arm in a sling, one carrying an infant with his face red with rage, its cries piercing. The monk was at the other end, at his dispensary.

His name was Bian. The abbot had assigned him to me, telling him that he would do what I wanted better than anyone, more discreetly. I'd been surprised at first how ready the abbot had been to help me, but Xingyu had explained things: the monastery, like a hundred others, had been half destroyed by the Chinese forces in 1959, and the monks were still painstakingly restoring it; their hate for the Chinese had burned on when the fire was put out, and they would help anyone who could free Tibet and leave them in peace.

Yelling the place down, the infant, as the mother shuffled forward in the queue. Bian, the monk, was talking to someone now across the counter, a man in a white coat, the dispenser, giving him the prescription. It had become grubby in Xingyu's wallet and had been much handled, and I'd improved on that, making a smudge across his name that had left it unreadable.

This was simply an exercise in caution. Quite apart from the world-media photograph of Dr Xingyu Baibing in London, the Chinese weren't likely to suspect that he was already back on the mainland. It's the last place they'd expect me to go, he'd told me on the boat in Hong Kong, and that was why Pepperidge and London had agreed to let him come to Lhasa. But I'd asked Bian to buy the insulin for me to cover the thousandth chance that we were wrong, or that one of the KCCPC agents who'd seen me making the snatch at Hong Kong airport was now here in Lhasa, and that they suspected I was still looking after him. So this was just routine, straight out of the book.

'I shall require another injection,' Xingyu had told me, 'by noon.'

He hadn't apologized for the trouble involved, hadn't realized there was a risk, however slight. He'd been squatting on the floor when I'd left him, writing busily, some kind of diary perhaps, that he'd have to leave behind him when we made our final move; if so, the abbot would look after it for him.

The monk, Bian, was nodding, putting money on the counter, hitching the red robe higher on his shoulder, taking a packet from the dispenser, coming away.

I left the clinic five minutes after him and cut him off in a cobbled street behind one of the temples, deserted except for a huddle of mendicants sheltering from the wind.

'I did not bring it,' Bian told me.

'The insulin?'

'This is aspirin. I bought it in case I was watched. The dispenser said he would give me insulin but warned me, saying he had orders to report it.'

Mother of God.

'To report any sale of insulin?'

'Yes.' He looked along the street, then back to me, the stubble on his face catching the light from the flat gray sky where the sun made a hazy disk, his eyes watering in the freezing wind. 'He was a Tibetan, and was sorry, but said he would lose his license, perhaps be arrested for disobedience.'

Perhaps I was just paranoid, losing my grip. There could be other explanations. 'Bian,' I said, 'how many places are there in Lhasa where you can get insulin?'

'Very few. Very few places.'

So they wouldn't have to put a standing watch all over the town, the KCCPC, though of course if they had to, they would do that. They'd got limitless manpower.