On the way, he stopped at a tiny village grocer's and bought himself a rough picnic: cheese triangles, potted meat, biscuits and a couple of tins of beer. He didn't want to show his face in any restaurant or bar around there. Then, once he had passed Ballina, he worked carefully up the east side of the Lough, snooping down every side road or track that could possibly lead to a boat. It took time and the drizzle turned to rain. He wished he'd thought of going up the far side of the Lough, where the road ran right along the shore, and using his field glasses. There couldn't be many houseboats around at this time of the year. Then he saw the Citroen, parked beside a gate in a field that stretched down to the water.

It might have been converted from one of the vast range of small landing craft sold off after the war. There had been dozens of different types, but all of them looking like half-sunken shoeboxes, and a lot had ended up as houseboats or small ferries. This one had a tall, split-level cabin built atop it, with wide windows and their inevitable net curtains, and even a window-box under each one. It was old and needed painting, but it still had a certain spartan strength. High as the cabin was, the wind might blow it over but wouldn't blow it to pieces, He walked over a creaking gangplank that was as good a warning as any barking dog, and stepped down into a tiny cockpit. There was a small steering-wheel on the cabin wall and a slot for an outboard motor at the back. Or did you say 'stern' for houseboats?

After a moment, he tapped lightly on the cabin door, where the varnish was peeling off in long thin scabs. Nothing happened for a minute, then there was a scuffle and a clang, and more silence.

Then a woman asked: "Who is it, then?"

Maxim took the chance. "I'm Major Harry Maxim, British Army, and I work in Number 10 Downing Street."

A pause. "Why don't you bugger off back there, then?"

"We traced you, Mrs Jackaman, because a Czech defector told me where to look. They won't be long, if they aren't here already."

"Just suppose I went down and told the boys in the bar that the British Army's invading Lough Derg?"

"I don't know, Mrs Jackaman. I don't know what'll happen when the other side gets here, either."

Another pause. "I might be more interested in seeing them than you buggers." Her voice, if not her language, was very pure and precise, as if she'd once taken elocution lessons.

"Then why are you hiding out here?"

"Bugger off."

"I'll be in my car in the lane."

He walked back across the gangplank, feeling her stare piercing his back, and up the soaking field to the lane. In the car, he turned on his pocket radio and started to eat the cheese and potted meat. At some time, the Escort's steering-wheel had been taken off and put back ninety degrees wrong, so that the plaque in the centre read F O R D He daren't tell George that; he'd say it was Very Irish, when it wasn't, it was Very Garage. He cut and spread the food with the illegal flick-knife, then wiped it carefully clean and put it back in his trouser pocket.

After twenty minutes she trudged up the field. He got out politely and waited.

She was smaller and dumpier than he'd expected – though he wasn't sure what he had expected – in a green tweed skirt, a short black leather coat cut like a double-breasted mac, and a headscarf knotted at the back of her neck.

"What if I asked you to drive me into town to see the Gardai?"

"I'd say it wasn't a bad idea."

"Let's see your ID, Major Whosit." She'd been a Ministry of Defence wife for a dozen years. Maxim took out his card; she studied it, grunted, then slumped into the passenger seat. He walked round and got in the other side.

"Do you want to go anywhere?"

"Just drive around. I get cooped up in there.'"

Maxim backed fast up the narrow lane. "Would you like some rather nasty processed cheese?"

"Sure." She fumbled the box, spilled the cheeses, rescued one from between the seats and started picking it open. She was lightly and inoffensively drunk, and Maxim wondered how much of that had happened after he knocked on the door. A round, plump and rather flushed face, a piggy nose and at least a double chin. Put kindly, she was a bit short on royal blood. Perhaps the elocution lessons had been a touching attempt to become a proper Diplomatic Wife.

"What's an infantry Major doing at Number Ten?"

"I hope I'm the first to find out. I was attached there after your husband died. The Prime Minister was rather annoyed with the security service."

"Oh, that's nice. Our masters are good at being right – after the event. Very well, Major, what's all this about?"

"Why is the KGB looking for you?"

"I put in a question and all I get back is a question. You're like one of those fruit-machines in pubs where all you get is tokens, never real money. And you said it was the Czechs, not the Russians."

"They usually use the Czechs or Poles for their leg-work outside London. Their own people can't go more than thirty miles without giving notice and saying where and when – it's retaliation for the rules they slap on us in Moscow. The same thing works for Dublin. I thought you'd have known that."

"I expect Jerry told me at some time. You can't remember everything."

"And did you approach them, first?"

"Who told you that?"

"I did say there'd been a defector."

She was quiet for a while. The rain kept coming down, and the tracks feeding into the road from the Arra Mountains on their right spread fans of mud and twigs across it.

"This is a bloody cold car," she said at last.

"The heater's on the blink."

She gave a cackle of laughter. "More cuts in defence spending?" The elocution hadn't reached as far as her laugh; it was plain raw meat.

"How did you get in touch with them? I wouldn't know where to start."

She looked at him sideways. "Really? You should read more spy thrillers. What you do is, you write them a letter – on Mo D paper so they'll take some notice of it – and then you don't post it or deliver it yourself. You drop it in at the Aeroflot office in Piccadilly and hope they'll have the sense to see it gets to the right people."

"And they did."

"If they hadn't, I'd have tried some other way. I wasn't going to risk another little visit from bloody Security."

He glanced at her; her mouth was clenched shut and her eyes fixed.

"And then?"

"Then… then they put a message in the Telegraph, a meaningless one I'd given them, to show they'd got my letter. So I sent them another."

"Did you say who you were?"

"Of course I did, man. I had to or they wouldn't have believed a thing."

Maxim had a weird disembodied feeling, like going under an anaesthetic. At Ashford they'd told him about traitors who had to confess, but this was ridiculous.

She had cheered up. "So then I told them they had to give me a telephone number which I could ring, and they did. They put it in the Telegraph in code: you added one to the first number, subtracted one from the second, that sort of thing, I'd told them how to do it, but I'm sure they'd be used to it anyway."

"I'm sure," Maxim murmured.

"So they never got to know where I was."

Abruptly, the high wooded banks on either side of the road ended and they came out onto an open headland overlooking the Lough. On a whim, Maxim swung off onto the turf and parked facing the water that rippled like stretched grey silk in the wind.

"Would you like a can of beer?"

"Surely."

He found the two cans on the back seat. She snapped hers open, took a quick drink, then started running the broken-off can ring up and down her finger until it just squeezed over the knuckle to touch the wide wedding band. She didn't know she was doing it.