Alan Turing (1912 – 1954)

Turing studied and taught mathematics at Cambridge University where he proved that automatic computation cannot solve all mathematical problems.

This concept, also known as the Turing machine, is considered the basis for the modern theory of computation.

After 2 years at Princeton University in America he returned to England in 1938 and began to work secretly for the British cryptanalytic department, the Government Code and Cypher School. Here he played a vital role in deciphering the messages encrypted by the German Enigma machine, which provided vital intelligence for the Allies. He took the lead in a team that designed a machine that successfully decoded German messages.

After the war, Turing turned his thoughts to the development of a machine that would logically process information. He worked first for the National Physical Laboratory (1945-1948). His plans were dismissed by his colleagues and the lab lost out on being the first to design a digital computer. It is thought that Turing’s blueprint would have secured them the honour, as his machine was capable of computation speeds higher than the others. In 1949, he went to Manchester University where he directed the computing laboratory and developed a body of work that helped to form the basis for the field of artificial intelligence.

In 1952, Turing was arrested and tried for homosexuality, then a criminal offence. To avoid prison, he accepted injections of oestrogen for a year, which were intended to neutralise his libido. In that era, homosexuals were considered a security risk as they were open to blackmail. Turing’s security clearance was withdrawn and he could no longer work for GCHQ.

He committed suicide on 7 June, 1954. The cause of his death was cyanide poisoning. A half-eaten apple was found besides his bed. Although the apple was never tested for cyanide, it is speculated that it was the means through which Alan committed suicide.

Turing’s work is now regarded as having provided the foundation of computer science and artificial intelligence.

Fun facts:

  • He kept his own mug chained to the radiator during his time at Bletchley Park, in order to stop others from using it.
  • Turing often cycled to work with his clothes worn over his pyjamas and even wearing a gas mask to keep his hay fever at bay.
  • It is often mistaken that the iconic image of the Apple logo, with the apple being half eaten, is a homage to Alan Turing. The man responsible for the design has said that the apple was bitten just to make sure people didn’t mistake it for a cherry. According to Stephen Fry, although Steve Jobs also confirmed that it wasn’t an intentional reference to Turing, he added “God, we wish it were.”


  1. I am one of the very few people (maybe the only one left) who knew Turing at Manchester University, when I was an undergraduate in the Electrical Engineering Department (later renamed the Computer Department).

    My recollection is that Turing was an Associate Professor and that Professor Fred Williams (not Alan Turing) was responsible for developing the Manchester Machine.

    I also knew the Berners-Lees (parents of Sir Tim, of Internet fame).

    After graduation I joined Ferranti Ltd and was involved in the development and production of their Mark 1* and Pegasus computers. Its a little hard to believe now (given that your smart phone has more computing power) but the Mark 1* sold for around half a million (1960) dollars.

    Although my memory is no longer as efficient as it used to be, I still retain a number of stories from that period, and (if provoked) I
    might offer some of them for your inspection.

    • thanks for comment JHH. It must be awesome knowing people like Turing and having had the chance to witness them in person. I’d be very interested to learn more if you are interested in sharing some stories please let me know via a short email using the contact form on this site. all the best from Europe.

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