I didn't like that word. He'd used it twice – it was a schoolmaster's word. I didn't like being tested. Who did he think I was – a fresh scout just out of the training-school?

Down there they'd got off their chests the aerial ballet of intricate patterns that bespelled the eye and the footlights came on again. Under the applause I said loudly: "I don't like being put through the hoop by an unknown contact right at the bitter end of a mission and I don't like my phone being tapped. How long has it been going on? "

Blandly he said: "You tell me."

The glow from the stage seemed bright after the gloom and I took a good look at his face. It was a round face and almost featureless. Mud-brown eyes behind schoolboy-type hornrimmed spectacles with plain glass in them that didn't magnify even by a fraction but good at their job since they made one bold feature for the blank face. Hair brown. Nothing to go on. If I wanted to recognise this man again I would have to watch him walk. Unnecessary. Tomorrow I'd be in England, therefore to hell with him.

I said quietly (the applause was dying away): "It hasn't been tapped for long or I'd have caught the clicks."

He began talking rapidly and softly with his hands to his face to focus the sound of his voice on my ear alone.

"I was flown out from London this morning with orders to make contact in strict hush. I wasn't allowed to go to your hotel or meet you anywhere in public, so that local Control had a difficult task. Your phone was tapped at some time before noon in the hope that we could find out your programme for the day and somehow provide contact for me, and it was most fortunate that we heard you telephone for a box at the Neukomodietheater."

"Played into your hands, like a fool."

I was pleased to see his look of mild pain. I was acting the rebel. Tomorrow I was being let out of school so tonight I could cheek whom I chose, and he was handy. Also he was a stranger and might be a top kick of some kind very high in the echelon, out here in the field to chuck his weight about incognito. If so I could be saucy and get away with it until he identified himself. The show wasn't turning out so badly after all.

He said: " This is all fully urgent."

It was the big signal, then. 'Fully Urgent' was Control's phrase for covering most of the other ones from ' Top Secret ' through ' Action at Once ' to ' Priority Red.'

He could keep it.

"Find someone else," I said. "I'm homeward bound."

I felt better now. The big signal wasn't for monkeying with, and I'd monkeyed.

The words came softly out of his cupped hands:

"KLJ was found dead last night."

It caught me like a blow in the face and I began sweating immediately because years of training had kept my eyes and mouth and hands expressionless as the shock of the words hit me, and the body, denied instinctive reaction, has to do something at a time like this; so I sat facing him with calm eyes and a quiet mouth and motionless hands, and felt the sweat coming.

He said: " We want you to take his place."

I told him they couldn't expect it of me.

He said it was a request, not an order.

Talking was difficult most of the time because the music would break suddenly now and then in a good imitation of the West Side Story style, and a word we had pitched against the volume of the orchestra would explode in a gap of silence. It was easier during the two intervals; we locked the door of the box and sat on the carpet with our backs to the balcony, unviewable even from the highest box on the other side of the auditorium; the murmur of the people gave good background cover for our voices.

One thought was lodged in my head like a bullet.

KLJ was dead.

I had asked Pol about it and he said: " Floating in the Grunewald See." So there was Kenneth Lindsay Jones's place. We all have a place. We know where we were born but not where we shall die. At home or a mile away at the crossroads or far across the face of the earth, not knowing it in our sleep or pitched down on the wet road or trapped in the wreckage on the mountainside and knowing it only too well. A place for each of us, and there was his, the lake at Grunewald renamed Kenneth Lindsay Jones by virtue of his presence.

We'd lost five men during my time at the Bureau but this one was said to be unkillable.

Pol had told me more because I had asked. "A very long-range shot in the spine from a 9.3 again, as it was with Charington."

Then we stopped talking about KLJ as if he'd never existed. Pol set about stalking me and I let him, sitting with my back to the balcony and listening to the quiet modulated tone that I was already beginning to hate.

"We are highly impressed with the way you have been working on these war-crime inquiries. There was no need for secrecy because the matter comes under the terms of the London Agreement, yet you chose to maintain strict hush and we have been told that even the chief of the Z Commission had no knowledge of the man responsible for the arrests. We assume that your reason was to keep in practice."

He waited for confirmation. I enjoyed my silence.

"Further, your operations have been on the periphery of a search-area that was opened at the Bureau three weeks ago, on pressure from Paris. No one – now – has more information on the Berlin nucleus of ex-Nazis and neo-Nazis than yourself. This now becomes invaluable to us and so do you."

He gave up waiting for me to help him along, and this was a danger I didn't see until it was much too late. By refusing to answer him even by a grunt I was letting him keep up a monologue in that soft and modulated tone that never gave pause. And it was hypnotic.

"Of the fifteen war-criminals you have indirectly arrested, five as you know were of major status, and we believe that the recent suicides of General Vogler, ' General Muntz and Baron von Taube were provoked by pressure from their own group rather than by the dictates of conscience."

He talked about the three prosecution witnesses found shot dead and facially mutilated. "They were not removed in order to decrease the number of witnesses at the Hanover Trials because there are as you know nearly one thousand of them, and the mass of evidence is such that one could remove ninety per cent of them and still remain certain of conviction. Those three were murdered in reprisal and we believe that there will, follow twelve more unless the Federal police can protect them. In all, fifteen. One for every war-criminal convicted. Further, the intention is to dissuade new witnesses from coming forward at the successor trials in Bonn and Nurnberg. They intend by terror tactics to ensure that the Hanover Trial shall be the last of its kind ever held."

I had his accent now, from the ` ur ' in ` Nurnberg '. He was a Rhinelander.

He talked about the seventy thousand Nazi refugees and self-exiles living in the German colony in San Caterina, Argentine, among them the Hitler deputy Bormann. "As you know, their Tacuara organisation carried out reprisals against the Jewish population following the Eichmann abduction."

I wished he would stop saying 'As you know,' or better, tell me something I didn't.

"But Zossen is here in Berlin."

He stopped. I knew why. I was hooked.

I said: " Heinrich Zossen?"

"Yes."

A thin man. Pale of face, with dewlaps and a pouchy mouth. Round-shouldered like his Fuhrer. Little blue eyes, the blue of ice. A voice like a reed in a winter wind.

I had last seen him twenty-one years ago, on an August morning when three hundred of them were lined up at the brink of the pit they had been made to dig from the rich earth of the forest of Briicknerwald. The birds had stopped singing when the SS staff car drew up and Obergruppen-fuhrer Heinrich Zossen got out. I watched him as he walked behind the lines of the three hundred naked men as if inspecting them. He turned and walked back and I watched him. He was a young man for his rank and proud of his uniform. He was not a thug. A thug would have taken a whip from a guard and drawn blood from even these bloodless buttocks for our amusement; he would have pointedly held his nose, reminded that these men had been moved a hundred and thirty miles through the night in sealed cattle-trucks, packed ninety to a truck; he would have taken his revolver and fired the first bullet himself, to lead the fun. He did none of these things. He was an officer.