Sergeant Gower came in, wearing a uniform anorak and cypress-green beret. He ignored Maxim, went straight to a cigarette machine and bought a packet of Marlboros. The barman gave him a sour look as he went out again, turning right. Maxim waited two minutes, then followed.

In the car, Gower said: "It's in place," and told him the address. "And if you want transport over there, there's a green Ladataxi that'll be hanging round the Friedrichstrassestation. You call the driver Erich-shall I give you the number?"

Maxim repeated it carefully. "Thanks. I'll push on across, then. It's asking a bit, but if you could stick around here and be ready to grab the Volkswagen if it comes back-I'll try and be with it myself, but… I don't know if you've powers of arrest…"

"In Berlin, we can always work out something."

"Fine. And if I don't get back, could you signal George Harbinger at Mo D?"

"You'll be back, Major." But it was the instinctive reassurance demanded on the eve of battle. Gower was torn-as Maxim could sense-between the common sense of letting him get on with his job and the feeling that nobody joined the Army to go into things alone. The Sergeant frowned through the windscreen and tapped his fingers quickly on the wheel. "I suppose I'm just the intellectual type, really… But there's something worries me. A Blowpipe's a good bit of kit, it did all right in the Falklands, I heard-but they shot off a lot more than they knocked down planes."

"Taking off, any aeroplane's a sitting duck. And they've been practising as much as they could."

"Civilians." The slow shake of Gower's head dismissed any civilian practice. "They've only got the one missile… it could have water on its brain or oil up its – Idon't know about missiles-but one on one isn't a sure way. Then what? What's their back-up plan?"

"I don't know."

"Me neither, Major… but killing the Archbishop, I mean it's quite a big idea. If they were going to do it at all, they might want to get it right."

"They could be thinking of an assassination in London-only they don't stand a chance, now we're on to them."

"Yes. I just thought, if he's not going to fly over that Blowpipe anyway, if you'd gone along to guard him instead…"

"He's only half of it. If the Blowpipe brigade gets picked up-"

"They must have thought up some sort of getaway. I mean, it would bugger their plan if they got caught…"

"I don't want them to get away. I want to bring them back alive and talking."

The Wall that cuts Berlin in half, and makes West Berlin a landlocked island, brings a variety of emotions. It is nasty, but that is something you knew already. It is strange, a wall cutting across streets, at one place running down the centre of a street, pedantically following the boundaries of the prewar electoral districts-but just how strange only a Berliner could say, and increasingly only an older Berliner-although West Berlin is an old people's city. But perhaps strangest of all, it is old-fashioned: a Cold War attitude frozen in concrete, immortalising midnight deals in cigarettes, currency, people. It brings an exasperated demand: For God's sake, haven't things changed just a bit? The Wall is the answer, and the answer is No.

What it certainly is not is impressive. Barely twelve feet high, it could be scaled in seconds by trained men or knocked flat by a tank: of course, the Russians may well have thought of that. On the Western side it is covered in aerosol graffiti and occasional plaques where people have died trying to cross from the East, but graffiti dominates. Its strength lies on the Eastern side, in the no-man's-land of minefields, watchtowers, alarm fences, ditches, automatic guns and vehicle obstacles.

Yet even these are not very impressive as you walk past them at Checkpoint Charlie; or perhaps soldiers just getblaseabout such things. Maxim noted them instinctively, at first pretending not to look, then gawping obviously, as he assumed a tourist would do. The pathway narrowed through wire fences and he found himself standing with a little group of real tourists on the wooden verandah of the long control shed, a dirty corrugated plastic roof overhead and a wire mesh gate ahead, waiting for his visa. And waiting. And waiting.

A single unarmed guard with a green-banded cap, chubby and pink-cheeked, strolled out among the cars on the widened roadway beside them, collecting and returning passports, lifting chain barriers to let a vehicle creep forward a few more yards to the next stage. From time to time he took a passport from a faceless window beyond the gate and held it up, open to show the photograph: a relieved tourist claimed it, was allowed through the gate to pay his five Deutschmarks, and vanished into the shed further along. The rest waited.

It became the timeless, mindless hospital hallway where you wait stripped of personality, because the real you is a clutch of paperwork being leisurely diagnosed behind closed doors; where the best news can only be that things aren't as bad as you are sure they are. Or that you will reach East Berlin.

It was a time for fears to grow. Absurdly, he began wondering if they had his photograph-Harry Maxim's photograph-on a file in that shed. They certainly had it on file somewhere behind the Iron Curtain, had had it from soon after he started work at Number 10, and he was a hundred miles behind the Curtain already. Or they were pulling the Winterbotham passport to pieces, spotting discrepancies and flaws he would never have suspected, that even Agnes… no, he didn't want to think of Agnes. She had nothing to do with Winterbotham. /am Alan James Winterbotham, aged thirty-seven, bom in London UK, hospital administrator… But there's a photograph of Harry Maxim-It was the guard holding up his passport.

Blindly, he took it."Danke schon…"

"Five Deutschmarks."

He paid at the window, barely seeing the shadowed face beyond, walked the verandah, in through the door… There was a shelf scattered with small forms in different languages. He found an English one and filled out how much currency he was carrying, handed it to a middle-aged woman in uniform.

"Have you any books, papers?"

He half-pulled the unmarked map from his pocket; surely most tourists would carry that.

"A map." She waved him past. "You must change twenty-five marks."

He was ready for that. At the next desk he got twenty-five East German marks on a one-for-one exchange; the unofficial but real rate was four to one. And he was 'free' in East Berlin.

The first stage of the route was easy: straight ahead down the wide Friedrichstrasse. Even after the deliberate desolation behind the Wall, the street took time to revive, with buildings perhaps eight storeys high standing among empty plots; one of the buildings itself was derelict. The wind blew a fine dust out of the emptiness, bringing a weird reminder of Washington… /am Alan James Winterbotham…

At the broad Unter den Linden the new buildings began, stretching out in either direction. He waited for a green light; the traffic was far thinner than in the West, the cars smaller: Skodasand Ladas, many old and asthmatic, with dulled paintwork. The crowd thickened on the far side, as he neared the Friedrichstrassestation; there were a lot of uniforms-all East German: the overt Russian presence in Berlin is very small-with the officers all carrying briefcases that were as much a badge of rank as their epaulets.

He found thecafeeasily, just past the three-level station complex and the Metropole Theatre. It was small and genteelly modern, with waitresses in white-frilled black uniforms weaving among tiny plastic-topped tables. He drank a coffee, black, and it tasted much as any coffee did, but he was no connoisseur; had the time-warp of the Wall made him expect something made from toasted acorns?