He returned a week later in triumph. Philby had confessed. He had admitted spying since 1934. He was thinking of coming back to Britain. He had even written out a confession. At last the long mystery was solved.
Many people in the secret world aged the night they heard Philby had confessed. I was nearly forty-five. It is one thing to suspect the truth; it is another to hear it from a man's lips. Suddenly there was very little fun in the game anymore; a Rubicon had been crossed. It was not the same as catching Lonsdale; that was cops and robbers. To find that a man like Philby, a man you might like, or drink with, or admire, had betrayed everything; to think of the agents and operations wasted: youth and innocence passed away, and the dark ages began.
A few days later Arthur stopped me in the corridor. He seemed strangely calm, for such a tense, almost hyperactive man. It was almost as if he had seen a bad road accident.
"Kim's gone," he said quietly.
"Good God, how...?"
Arthur smiled weakly. "It's just like 1951, when the boys went..."
Philby's defection had a traumatic effect on morale inside the senior echelons of MI5. Until then, theories about the penetration of MI5 had been nursed secretly; afterward they became openly expressed fears. It seemed so obvious that Philby, like Maclean before him in 1951, had been tipped off by someone else, a fifth man, still inside. And of course, the possibility of a fifth man chimed completely with Golitsin's evidence about a Ring of Five. Burgess, Maclean, Philby, almost certainly Blunt, and a fifth. Someone who survived 1951, who stayed on undetected, who even now was watching the crisis unfold.
Hugh Winterborn and I often talked about the subject. He was convinced that we were penetrated at a high level.
"I just can't believe we are as apparently incompetent as we appear to be," he used to say.
Operation CHOIR, where we found the Russians had blocked up the pinhole for our probe microphone, had a major effect on his thinking, and even eight years later he used to talk animatedly about it. There were other incidents, too, which made him suspicious. We installed SF on the Chinese Embassy telephones, and almost immediately the Russians went around and took it out. Then there was the Falber Affair. After the PARTY PIECE operation, MI5 went on the hunt for the CPGB files which listed the secret payments made to the Party by the Soviets. We suspected that perhaps they might be held in the flat of Reuben Falber, who had recently been made cashier of the Russian funds. Falber is a prominent CPGB member, so when he advertised for a tenant to live in the flat on the ground floor of his house, we installed an agent there. Almost immediately, as we were planning to burgle the flat above, the agent was evicted by Falber, who gave no reason for the eviction.
But as a wave of anxiety passed through Leconfield House, I was still marooned inside the Directorate of Science. I decided to make my own freelance inquiries. Over a period of months I slowly drew out files from the Registry. First I took out the files for the microphoning operations I had been involved with in the mid-1950s - Operation CHOIR in London, DEW WORM and PIG ROOT in Canada, all of which went inexplicably wrong, and MOLE in Australia. I examined the cases carefully. Each had failed, and although complicated hypotheses to explain each failure could be adduced, the possibility that each had been blown by a spy inside MI5 was also a serious one. Then there were the cases which preoccupied Winterborn. Again, alternative explanations could be found. Maybe we had been clumsy. Maybe Falber just guessed the identity of our agent, but I find it very difficult to believe. A leak was just as possible. Next I pulled out the files on each of the double-agent cases I had been involved with during the 1950s. There were more than twenty in all. Each one was worthless. Of course, our tradecraft and Watcher radios were mainly to blame, but the Tisler affair had left a nagging doubt in the back of my mind. The Lulakov-Morrow test did not exclude the possibility of a human source beyond the monitoring of our Watcher radios. Then there was Lonsdale, and lastly Philby. Again the same pattern. Not one single operation had succeeded. as planned, and all had some degree of evidence of Russian interference.
There is a point in any mystery when the shape of the answer becomes suddenly clear. Over those unhappy months in Buckingham Gate, in the winter of 1962-63 as I pored through the files, back-checking and cross-checking the complex details of nearly eight years of frantic work, it all became suddenly very obvious. What until then had been a hypothesis, became an article of faith. There was a spy; the only question was who? More weeks were spent laboriously checking the dates when files were signed off and on, when access began and when it ended. And always it came down to the same five names: Hollis, Mitchell, Cumming, Winterborn at a stretch, and I myself. I knew it wasn't me; Hugh Winterborn never really fitted, and I knew it could not be him; Cumming I dismissed from the start. He would never have had the subtlety to carry it off. Which left Hollis and Mitchell. Was it Hollis, the aloof, pedestrian autocrat with whom I enjoyed a civil but distant relationship? Or Mitchell, his deputy, a man I knew less well? There was a secretiveness about him, a kind of slyness which made him avoid eye contact. He was a clever man, clever enough to spy. I knew my choice would be based on prejudice, but in my mind I plumped for Mitchell.
Early in 1963 I realized that one of the two men knew what I was doing. When I began my private investigations, I used to place the files in my safe on top of minute pencil marks, so that I could tell if they were being moved. One morning I came in, and they had been moved. Only two men had access to my safe: the Director-General and the Deputy, who retained copies of all combinations. The shadows were gathering; treachery stalked the corridors.
After Philby's defection Arthur became curiously distant. I could see he was preoccupied, but he deftly turned aside all attempts by me to find out what he was doing. I spent several evenings with him at his flat near Euston Station, and although we discussed Golitsin in general terms, he refused to be drawn out on what further inquiries he was making. Convinced that I might be sacked at any moment, or at least removed from access in some way, I began to make excuses to visit Arthur's office after hours, bringing with me files which I had used in my freelance examination of thirty-eight cases.
"Do you think that's significant?" I would ask, drawing his attention to a small ambiguity in the handling of a double-agent case, or an unexplained termination of a microphoning case. Arthur invariably gazed silently at whatever it was I showed him, thanked me, and said nothing more. Finally one night Arthur said to me, "You know who it is, don't you, Peter?"
I said, "Well, it's either Roger or Graham."
He said that he was carrying out an investigation of Mitchell. He told me that he thought there had been a leak which had led to Philby's defection. He too had come to the conclusion that it was either Roger or Graham but he did not know which, so after Philby defected he had gone to Dick White and put the whole problem to him. Dick was his mentor, the man who gave him his head in the late 1940s, and Arthur never forgot the debt he owed. Dick asked him to come back and see him the next day when he had had time to think about it. This Arthur did. Dick had been very sensible. He was sure Roger could not be a spy, but he felt it was possible of Mitchell. He advised Arthur to tell Hollis of his fears, and as a result Hollis instructed Arthur to begin an investigation of the Deputy Director-General. He had been doing this for a short time until he and I exchanged ideas.