Computing with Quantum Cats by John Gribbin Read Free Book Online Page B

contained “all the elements to make a general-purpose device”—a Turing machine. 14
    At the end of the war, Bletchley Park could (and I would say, should) have become a scientific research center, equipped with ten Colossi and a world lead in computing. Instead, on the direct orders of Winston Churchill (who did many questionable things to set alongside his greater moments), all but two of the machines were physically brokenup and most of their components smashed. This was part of a successful attempt to hide the success of the codebreaking work which had substantially shortened the war, so that the British could carry on reading the coded traffic of other nations without being suspected. The “other nations” included the Soviet Union, which used captured German Tunny machines long after the war. In April 1946, the codebreaking headquarters moved to Eastcote, a London suburb, and changed its name to the Government Communications Headquarters (GCHQ); GCHQ moved on to Cheltenham, its present home, in 1952. In both these moves, it took with it the two remaining Colossi (“Colossus Blue” and “Colossus Red”); the work they did is still classified. One was dismantled in 1959, the other in 1960. But all is not quite lost; a replica Colossus has been built at Bletchley Park, which is now a museum, and can be seen there in all its glory.
    As machinery was physically destroyed, so papers were burned and the codebreakers were all sworn to secrecy—and they all kept their secrets, in many cases taking them to the grave. The attitude that wartime secrets should not be inquired into was shared by people outside Bletchley Park. When I asked Betty Houghton what she had said to her parents when they inquired about her war work, she replied, “They never asked.” The story of Enigma did not emerge properly until the 1970s, and that of Colossus became known in detail only after a crucial document, called General Report on Tunny and written in 1945, was released in 1996 under the American Freedom of Information Act. Deliciously, it is now available online to anyone with a Turing machine. 15
    Tom Flowers, the man who designed and built the first electronic computer, never imagined that the secrecy wouldlast so long. Although he was granted £1,000 by the government at the end of the war, this did not cover his personal expenditure on Colossus, so he was actually out of pocket as a result of his work. Flowers was also awarded the MBE (the same honor later awarded to The Beatles), for work designated simply “secret and important”: no details were given. His career was hamstrung by the fact that he could not reveal anything about his wartime work, and so was unable to persuade his superiors to pursue the development of electronic telephone exchanges in the post-war years. This may sound trivial, but in these days of instant global communication it is hard even for those who were around at the time to remember how primitive telephones were even in the 1950s, when “long-distance” calls (that is, anything out of town) still had to be connected by a human operator plugging leads into the appropriate sockets. It was ten years after the end of the war before the Post Office began to move into the electronic era, missing out, apart from anything else, on the opportunity to boost British exports at a time of economic hardship. But Flowers lived just long enough to see the importance of his work beginning to be recognized by the computing community. He was able to give a talk in Boston in 1982 which lifted a corner of the veil of secrecy, and in 1997, on the occasion of his own eightieth birthday, Bill Tutte gave a talk detailing the way Tunny was broken. Thomas Flowers died in 1998 at the age of ninety-two.
    Unlike Flowers, Alan Turing was able to pick up the threads of his wartime work after the completion of the Delilah project in 1945. He too was “honored” by the