There was a taxi outside the Excelsior and I got in.

'Mauritius Hotel.'

The streets swung past and I shut my eyes, lingering flight-disorientation and nothing to have to watch, everything under control. One certainty: she wasn't an agent, either ours or theirs. One probability: Tewson had been. But there were inconsistencies because everything fitted so well and then came apart: he'd presented a classic cover in his dossier, lowly work for a government department, three-year-old Austin and a few small debts and never travelling until Spain (to establish the new image) and then suddenly Hong Kong, three trips in a row and then careless, leaving a widow, no children. All right, started off in DI6, ferreting around Portsmouth and places, then seconded or transferred to MI5 for missions abroad, a feint in Spain and then the Far East theatre, something strictly specific and confined to Hong Kong as a base for the South China seaboard area. Then the classic sequence: approach from Pekin, temptation, defection, exposure, elimination, but not before he'd been paid enough for his widow to blow it on Ming. Chief inconsistency: MI5 are a grotty lot but they wouldn't have given him the terminal handshake, they'd have sent him back to London for the full fourteen-year stretch, justice seen to be done, so forth.

I'm so bloody frightened.

Because she'd known about it and couldn't stop it running. But Tewson had stopped running and she was still frightened so what was running now?

South and then west again into Hennessy Road, a dark bundle of clothes on the pavement and some police around it, the end of the opium trail. We began slowing.

'Mauritius Hotel,' the driver said.

I got out and paid and under-tipped to provoke an argument because the lights weren't too bright here and I wanted to make it easy, oh all right then, here you are, but you people are bloody robbers, and he went away happy as anything with a Hong Kong dollar.

I went into the hotel and nodded to the night-clerk when he woke up, taking the stairs. The first-floor passage was conveniently long and I walked nearly to the end, thinking it could of course have been Nora Tewson herself who'd pushed the poor bastard into it, like Mrs Tuckman: she was hooked on money and there might have been quite a lot of it from Mao if Tewson had something they particularly wanted.

I got my keys and pushed one of them against the door of the cleaner's closet and then opened it, going in and shutting it, nothing but bloody brooms everywhere, pitch dark, don't tread on anything, there may be a bucket. Standing against the wall I thought the only thing she'd said that was really interesting was about his work, and even that had been clumsy: Pretty important, well, I mean it was important that he worked there, actually his work wasn't important, to tell you the truth.

Most of what she'd told me was in his dossier and the rest I could check on. His cover had been something in technical or engineering, design or research or development, him and his slide-rule, she wasn't bright enough to make that up or deliver it without over-acting. Some kind of cleaning-fluid stinking to high heaven, ammonia in it, eyes accommodating now, faint light from a ventilator above me. I couldn't hear him but I didn't expect to: There was carpet in the passage and he'd walk quietly, coming just far enough to note the number of the room next to the closet, then going away.

The watch was probably changed at midnight: this one was shorter and quite a bit older, no glasses, quite good, turning away when I'd come down from her apartment and through the lobby, nearly missed him. And a Morris, not the Honda, keeping such a big gap that I thought I'd better stand there arguing with my cab-driver to give him a bit of time. I don't even know who you are, Clive, who are you, got quite excited when I'd mentioned bullion, I'd better pick up a tag tomorrow and take him to one of the dealers they'd given me in Credentials and then lose him afterwards, somewhere near the Singapore.

Check: I'd given him enough time to reach the top of the stairs before I was halfway along the passage and there hadn't been any cover because the doors weren't recessed so he'd have had to wait there in case I turned round, and from that distance and from that fine angle of view, almost zero degrees, he couldn't see if I were going into the closet or the room next door. Satisfactory: given him five minutes to clear.

Proposition: she was still frightened so something was still running and she knew it and she knew what it was and London had given me the key to Mandarin at the outset: Nora Tewson. But I didn't know if Mandarin was their name for an opposition project they wanted me to penetrate or survey or destroy, or the name of my own mission on the files, and it was beginning to look a bit like a counter-intelligence thing. I didn't mind that: it could be a legitimate penetration job either way and that was in my field, somewhere to go into and go into alone, a prescribed target and access availability and a safe-house for signals and refuge. So far there hadn't been any problem: since touch-down at Kai Tak I'd checked the safe-house, made the contact with Nora Tewson, noted the opposition surveillance, gone in under it to develop the contact and established a false base, Room 12, Mauritius Hotel. The sole hazard potential was Flower and as soon as possible I'd have him recalled to London.

I turned the handle of the door and it took ten seconds to push it open one millimetre, the diameter of the human pupil in artificial light. Field clear. Stairs, lobby, street, check, re-check, clear. I had to walk as far as the Luk Kwok before I found a taxi.

'Orient Club.'

'You want nice Chinese girl?'

'No, just the Orient Club.'

Got out and paid him and watched him away. Re-check: clear. The street very quiet in the pre-dawn hour, no lights anywhere on this side of the consulate, a haze of gnats floating below the lamp near the sand-bin. Notice of Opportunity to pay Fixed Penalty, so forth, put it with the other one, some people collect absolutely anything these days, check ignition wires and start up. Final check: clear.

There were no messages for me at the Hong Kong Cathay and I went straight up to my room and opened the door and froze.

It's not only dogs.

The room was at the rear of the hotel and on the top floor. It faced north-east and at this moment the first light was coming into the sky above the theatre and the trees in the park. The shutters were half open, the way I'd left them, making a silhouette against the ashy light. My cases were on the stand, the way I'd left them.

It's not only dogs that have a sense of smell, the ability to sense alien presence in the environment, or its recent presence. All animals have it, but in varying degrees of refinement. In humans it has been atrophying over the decades since they began living with machines and relying on lights, locks and mechanical systems, but in creatures of the wild it remains highly developed. In creatures of the wild and in those few of us who express and incur mortal enmity in pursuit of our complex purposes.

There was no actual smell that worried me. In the short time I'd spent in this room I had become familiar with the subtle blend of sandalwood, jute, linen, polish, Jeyes Fluid and the ingrained odours of the human body. Nothing was different about the smell. There was no particular sound. From somewhere in the hotel I could hear the clack of mah-jong pieces and the far faint jangle of an alarm-clock, but they weren't loud enough to prevent my detecting human breathing in the room here, if there were any human near me. There was nothing to be seen but faint light, shadows, areas of near-darkness, and various objects occupying positions familiar to me. The shutters, the cases, shoes, hotel literature, doors, lamps, bathrobe, everything I could see in the dim light was as I had seen it last.