Time was now 9.07 and the depression was setting in because of the blood on her legs and the way Oktober had simply left the arena. It wasn't going to work and he didn't yet know that, so it would take him a short time to understand and alter his tactics – unless the doubling were perfect.

I am never happy when the adverse party gets confused because there's the interim period of correction and he is for this period like a mad bull that won't run straight, and you're closer to a high cornada than you'd ever be with an honest five-year-old Miura running on rails.

It took something like an hour to collate all the findings that stemmed from the events of the innocent afternoon, and to edit them and form detailed conclusions. General inference: starting out to hunt Zossen I'd been forced on the defensive twice within the first five days and hadn't learned more than half a dozen names that weren't already logged in the memorandum. The offensive would have to be taken as soon as possible because once Oktober decided that I knew nothing except what his and Fabian's questions had implied, he would have me wiped out before I started getting solid facts and feeding them into Control.

One vital check had to be made before I chose my offensive position, and it had to be made now.

The distance was some three kilometres and the pavements were drying so I left the BMW 1500 in the lock-up at the hotel and walked. Within five minutes I sensed a tag and led him north-west along the Hildburghauser-strasse at a slow pace because his presence had mentally thrown me and I wanted time to think. I hadn't expected him.

Findings: he must be flushed. I was reluctant to do this because he had his uses, but it was no go. What had happened was that no one had tagged me from the Grunewald Bridge until the beginning of the afternoon when I arrived at Inga's flat, because they'd known I could be picked up there. They hadn't known my new base: the Hotel Zentral. But they'd put a tag on wheels behind me when I had driven in the BMW from her flat in Wilmersdorf to the Zentral in Mariendorf – and I hadn't known it. It was simply that Oktober was taking no chances and this was pleasing because it showed how worried he was.

They now knew my present base. This man had tagged me from there and was still at work. That was all right because there was absolutely no way of going over to the offensive without first showing Phoenix my new base: to reach them I must first let them know where to reach me.

But I was committed to making this vital preliminary check, and it had to be done solo. Therefore he must be got rid of.

He was first-class and it took almost an hour. The whole business of tagging is one of the most routine and boring aspects of any operator's work. He can never walk down a street without making constant checks especially if he is going somewhere strictly hush, and it can burn up valuable time in having to flush the tag once he senses him. But if the game goes on long enough and you know the rules it is impossible to tag a man and not eventually lose him if he doesn't want you there, in a city the size of Berlin. I have lost hundreds and hundreds have lost me. In a few cases the boredom of well-worn tactics becomes over-ridden by the interplay of the game itself, and this is what now happened.

He was damned good and I had to take him through four hotels and twice through Lichterfelde-Sud station before I flushed him at the south end of the Berliner-strasse and took up my original course.

Time was now 11.21 and the bar was closing. It was called the Brunnen and I had never been there before. The kellner viewed me from between the chair-legs with his night-pallor face and thought out what phrase he would choose if I asked for a drink. There was only one other man in here, half-way up a step-ladder winding a clock; he didn't even see me come or go.

I asked the kellner the way to Sudende station and went back into the street, making a whole series of rapid checks.

It was completely clear. I was alone. It was, in a way, a big moment in my life, and I savoured it. The night air felt clean in my lungs and my shoes were springy on the empty pavement and for a few minutes I was aware of the remote possibility of the ultimate redemption of mankind. This modest turn of madness had the effect of a whiff of ammonia, clearing the head. It was a feeling that some operators may or may not experience once or twice in their careers. In actual speech it would go:

Here you are again in the thick of a job that you're doing because you choose to do it even though it may kill you round the next corner. It gets in the hair and the eyes and mouth and you never feel really clean, except for these few minutes, because you've just struck a blow that was bone on bone and it sent them reeling. Drink, brother, this may not come to you again.

My day ended in this way. It was midnight when I got back to the hotel. I fell asleep like an innocent man, with all those scars on the mind quietened as if by a balm. Tomorrow the offensive would be launched at dawn when the streets would be empty.

The dawn offensive was not spectacular, opening as it did with nothing more than a quiet stroll.

He was waiting for me when I left the Hotel Zentral. I didn't actually see him but I knew where he was. The street was residential but had a bar at the corner, some small distance from the hotel entrance. I knew he would be there. It was the only place. He would be somewhere behind the grey-white net curtains, watching for me.

To warm him up I turned along the street in the other direction so that he had to get out of the bar and start his tag at a distance. He wouldn't like that. There was nothing moving in the street at this hour but myself, and the morning was windless. He must have tracked me over this first section with his fingers crossed hard: I had only to turn my head once to spot him. I didn't turn my head. We went north towards the centre of the city where it would be more crowded.

The operation we were now engaged on was known as the switch. When an operator starts out to shadow another the outcome will be found among five main possibilities. One: the tag is never noticed, and the shadowed man leads the adverse party to his destination, unknowing. (It seldom happens. An operator who doesn't even notice a tag isn't allowed to stay in the business very long.) Two: the tag is noticed but can't be flushed, in which case the operator must simply lead him a dance and leave his original destination unexposed. Three: the tag is noticed and then flushed, and the operator can then make for his original destination unaccompanied. Four: the tag is noticed, flushed and challenged. (I did this with young Hengel. In that case my tag was not an adverse party, but it makes little difference: there's always a temptation to challenge after flushing, if only to see their face go red.) Five: the tag is noticed, flushed and followed. The switch has been made, and the tag is now tagged.

We don't often do it, because an operator is never off duty. He is always going somewhere and usually it's important that he gets there as soon as he can. On this occasion I used the switch because I had to go over to the offensive and find where the Phoenix had its nest. It might be where I had been taken for the narcoanalysis session, but I was getting bored with being taken to places and followed to places (Inga's flat). The idea was to draw the enemy's fire so that we could come to grips, and I had done that successfully, but it was no good fetching a bellyful of amytal whenever we closed together. I now had to find their base, go in under my own steam, get information on it and then get clear with the skin on.