The next morning I met the Post Office team over at St. Paul's and we drove over to the Embassy in their van. The security was tight at the Embassy door and we were escorted from room to room. The cipher room was in an annex, the Hagelin clattering away inside. Three cipher clerks were busy operating the telex machines and processing the diplomatic cables. I looked carefully for any signs of spare tape waste, but the section seemed well organized and tidy. One of the clerks came out and engaged our escort in animated conversation. After a while he went back in and turned the machines off. When he reappeared he came over to me and gesticulated toward the telephone. He could speak no English, but through sign language I understood that he wanted me to move the telephone closer to his seat near the machine. Scarcely able to believe our luck, I began to extend the cable, slowly turning my back on him so that the engineer could slip the small washer into the receiver to modify it for SF. I placed the telephone back on top of his desk, not more than two feet from the Hagelin machine. The clerk tapped it, and grinned at me broadly. I grinned back, but somehow I felt we were not quite sharing the same joke.
I hurried back from the Egyptian Embassy to the seventh floor to monitor the sounds from the receiver. It seemed at first to be an electronic haze, but after some fine tuning the clatter of the Hagelin was clearly audible. MI5 arranged a special link down to GCHQ, and every morning, as the clerk reset the machine, GCHQ's H Division calculated the new settings and read the cipher straight off, a process known as "leading the machine." The new technique of breaking ciphers by detecting intelligence about the machines through technical surveillance became known by the code word ENGULF. It was a vital breakthrough. The combined MI5/GCHQ operation enabled us to read the Egyptian cipher in the London Embassy throughout the Suez Crisis. The Egyptians used four different key ciphers worldwide, and by mounting operations against their embassies abroad using the same ENGULF technique, we were able to break into most of the other channels. The operation against the Egyptian cipher was a tremendous success for MI5. It came at a time when MI6 had conspicuously failed in their efforts to provide intelligence. Virtually their entire network in Egypt was rounded up and arrested on Nasser's instructions at an early stage in the crisis, and their only contribution was a bungled attempt to assassinate Nasser.
For Hollis, who had stepped into the Director-General's chair just as the Suez Crisis reached boiling point, the triumph could not have been better timed. It gave him a solid achievement in those crucial first few months. In the light of later events, I always thought it ironic that it was I who had given it to him.
The single most important intelligence which we derived from the cipher break was a continuous account of Egyptian/Soviet discussions in Moscow, details of which were relayed into the Egyptian Embassy in London direct from the Egyptian Ambassador in Moscow. The information from this channel convinced the Joint Intelligence Committee (JIC) that the Soviet Union were indeed serious in their threat to become involved in the Suez Crisis on the Egyptian side. One message was particularly influential. It detailed a meeting between the Soviet Foreign Minister and the Egyptian Ambassador in which the Russians outlined their intentions to mobilize aircraft in preparation for a confrontation with Britain. The panic provoked by this cable, which was handed straight to the JIC, did as much as anything to prompt Eden into withdrawal. Similarly, since all GCHQ product was shared with its American counterpart, the National Security Agency (NSA), the intelligence, I am sure, did play an important part in shaping American pressure on Britain to end the crisis.
Soon after the SF was installed inside the Egyptian Embassy we nearly lost the whole operation. The Russians, anxious to bestow client status on Egypt as the Suez Crisis deepened, sent a team of Russian sweepers to sanitize their London Embassy of any bugs or microphones. It was the sort of friendly gesture the Russians loved to bestow, enabling them to pick up useful intelligence for themselves at the same time. Our static observation post overlooking the entrance of the Egyptian Embassy detected the Russian sweepers as soon as they entered the building. I was called up to the seventh floor to monitor their progress in the cipher section. I listened helplessly as they entered the cipher room. They started with the fuse box and then began electronically sweeping the walls and ceilings with large instruments which looked like metal detectors. The microphone thumped ominously as a Russian hand picked up the telephone and began to unscrew the bottom. There was a muffled pause, and then the sound of the telephone being reassembled. Hugh Winterborn breathed a sigh of relief.
At the time we knew that the Russians had discovered the SF and would remove it if they found it, but they didn't! If the Russians knew about SF, which they did, and were so wary of it, for instance in the Russian Embassy, why had they overlooked it in the Egyptian Embassy? It would suit them not to alert us to the fact that they knew about SF, so that we would continue to use it. They could, after all, have sent intelligence via their own cipher circuit, Moscow-London, and handed the message over to the Egyptians in London. This would have been unbreakable. But I believe that there was another reason. The Russians wanted us to read the signals of their resolve in the Suez Crisis correctly. They did not want us to assume they were bluffing. The best way of ensuring we took their posture seriously would be if we obtained intelligence about it from an unimpeachable source, for instance from a secret cable. It was my first insight into the complexities of Soviet disinformation.
After the Suez Crisis had collapsed, I began to pester GCHQ again with suggestions of future cooperation. But they seemed to want relations to drift back to the languid state they were in before. And GCHQ, while happy to take the results of ENGULF, were unwilling to step up their help, in return, for MI5. In short, they did not mind MI5 working for them, so long as the arrangement was not reciprocal.
I felt that GCHQ had a major role to play in helping MI5 confront the Soviet espionage networks in the UK by tackling Soviet spy communications. The Russian Intelligence Service has always favored running really sensitive operations "illegally," using agents who operate entirely independently of the "legal" Embassy Intelligence Officers, communicating with Moscow Center by using their own radio transmitters. I felt sure that if we devoted effort to tracing and logging these transmissions we might get a break which could lead us right into the heart of the Soviet Intelligence apparatus. I wanted GCHQ to provide MI5 with the service that we had received from RSS during the war, of continuous monitoring of illegal radio broadcasts to and from the UK. It seemed to me to be straightforward common sense. But GCHQ were devoting a paltry one and a half radio positions to taking this traffic. It was a pathetic effort, and no amount of persuasion could make them devote more.
Shortly after the first ENGULF Operation against the Egyptian cipher I went to Canada to plan Operation DEW WORM. Toward the end of the trip Terry Guernsey, the head of RCMP Counterespionage, asked me to study an RCMP case which had recently ended in mysterious circumstances. During this review I ran across a detail which convinced me beyond any doubt that GCHQ had to be forced to change their mind. Guernsey showed me into a private room. Sitting on the table were three volumes of files marked KEYSTONE. The KEYSTONE case began in 1952, when a Russian entered Canada under a false name, intent on developing cover as an illegal agent for the KGB. In fact, his eventual destination was the USA, but the KGB often send their illegals into Canada first to establish for themselves a secure "legend," or false identity, before going across the border. But soon after the illegal, code-named Gideon by the RCMP, arrived in Canada he fell in love with a woman. It was strictly against KGB rules, and it wasn't long before Gideon developed doubts about his mission.