Free Spycatcher by Peter Wright

since.

    Hugh Winterborn arranged for the link to be relayed into a closed room at the far end. We sat down and waited for the interrogation to start. In fact, to call it an interrogation would be a travesty. It was an in-house MI6 interview. Philby entered and was greeted in a friendly way by three former colleagues who knew him well. They took him gently over familiar ground. First his Communist past, then his MI6 career and his friendship with Guy Burgess. Philby stuttered and stammered, and protested his innocence. But listening to the disembodied voices, the lies seemed so clear. Whenever Philby floundered, one or another of his questioners guided him to an acceptable answer.

    "Well, I suppose such and such could be an explanation."

    Philby would gratefully agree and the interview would move on. When the pattern became clear, Winterborn fetched Cumming, who strode into the office with a face like thunder. He listened for a few moments, slapping his thigh. "The buggers are going to clear him!" he muttered. Cumming promptly sent a minute to Graham Mitchell, the Head of MI5 Counterespionage, giving an uncharacteristically blunt assessment of the MI6 whitewash. But it did no good. Days later, Macmillan got up in the House of Commons and cleared him. I realized for the first time that I had joined the Looking-Glass world, where simple but unpalatable truths were wished away. It was a pattern which was to be repeated time and time again over the next twenty years.

    The Philby interview gave me my first experience of the MI5 surveillance empire. The seventh floor was, in fact, only one part of a network of facilities. The most important outstation was the headquarters of the Post Office Special Investigations Unit near St.
    Paul's. MI5 had a suite of rooms on the first floor run by Major Denman, an old-fashioned military buffer with a fine sense of humor. Denman handled the physical interception of mail and installation of telephone taps on the authority of Post Office warrants. He also housed and ran the laboratory for MI5 technical research into ways of detecting and sending secret writing. Each major sorting office and exchange in the country had a Special Investigations Unit Room, under the control of Denman, to place taps and intercept mail. Later we moved the laboratories up to the Post Office Laboratory at Martlesham, Suffolk. Then, if a letter which had been opened in St. Paul's needed further attention, it was sent by motorcycle courier up to Suffolk.
    Denman's main office was lined with trestle tables running the length of the room. Each table carried mail addressed to different destinations: London letters on one side, Europe on another, and behind the Iron Curtain on a third. Around twenty Post Office technicians worked at these tables opening pieces of mail. They wore rubber gloves so as not to leave fingerprints, and each man had a strong lamp and a steaming kettle beside him. The traditional split-bamboo technique was sometimes used. It was ancient, but still one of the most effective.
    The split bamboo is inserted into the corner of the envelope, which is held up against a strong light. By turning the bamboo inside the envelope, the letter can be rolled up around the slit and gently pulled out

    Where a letter had an ordinary typed address it was sometimes torn open and a new envelope typed in its place. But to the end of my career we were never able to covertly open a letter which had been sealed at each edge with Sellotape. In those cases, MI5 took a decision as to whether to open the letter and destroy it, or send it on in an obviously opened state. Pedal-operated microfilming cameras copied the opened mail and prints were then routinely sent by the case officer in charge of the interception to the Registry for filing.

    Denman's proudest memento was a framed letter which hung on the far wall. It was addressed to a prominent Communist Party member whose mail was regularly intercepted. When the letter was