- Alan Turing Part 1 -

Alan Turing, his life
and 'The Imitation Game' - Part 1

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'CODEBREAKER' was an exhibition developed by the Science Museum in London to celebrate the centenary of the birth of this pioneering British figure.

The following edited information has been largely obtained from and with acknowledgement to the Science Museum website, and also including the Colossus-Computer.com website, Wikipedia and various other sites.   Most of the pictures were taken at the Science Museum Exhibition or at Bletchley Park by this website's author.

Alan Turing is most widely known for his critical involvement in the codebreaking at Bletchley Park during the Second World War. But he was not just a codebreaker.

This British mathematician was also a philosopher and computing pioneer who grappled with the fundamental problems of life itself. His ideas have helped shape the modern world, including early computer programming and even the seeds of artificial intelligence.

The exhibition told the story of Turing and his most important ideas.

At the heart of the exhibition was the Pilot ACE computer, built to Turing's ground-breaking design. It is the most significant surviving Turing artefact in existence.

Alongside this remarkable machine was a sequence of exhibits showcasing Turing's breadth of talent. The exhibition offered an absorbing retrospective view of one of Britain's greatest twentieth-century thinkers.

The exhibition was visited by this writer in 2012. It closed on 20 October 2013.



"THE IMITATION GAME" is described as a "2014 historical thriller film about Alan Turing".

It stars Benedict Cumberbatch as Turing and was directed by Morten Tyldum, with a screenplay by Graham Moore based on the biography 'Alan Turing: The Enigma' by Andrew Hodges.

It had its world premiere at the 41st Telluride Film Festival in August 2014 and featured at the 39th Toronto International Film Festival in September where it won 'People's Choice Award for Best Film'.

It had its European premiere as the opening film of the 58th BFI London Film Festival in October.

In terms of historical accuracy, "while the broad outline of Turing's life as depicted in the film is true, a number of historians have stated that elements within it represent distortions of what actually happened."

These arise especially in regard to Turing's work at Bletchley Park during the war, his relationship with friend and fellow code breaker Joan Clarke and 'insulting' suggestions regarding his loyalty to his country.

The portrayal in the film of Cdr Alastair Denniston, his chief at Bletchley, is also criticised.   For details please click here.   The 'real' wartime Cdr Denniston is pictured on the right.

A comprehensive critique of the film may be found in 'The Guardian' newspaper - please click here.





Alan Mathison Turing, OBE, FRSA was born in Maida Vale, London on 23 June 1912. After leaving Sherborne School, Turing studied at King's College, Cambridge from 1931 to 1934.

Here he gained first-class honours in mathematics and in 1935 he was elected a Fellow of his college.

This was on the strength of a paper in which he proved the 'central limit theorem', despite the fact that he had failed to find out that it had already been proved in 1922 by Jarl Waldemar Lindeberg!

He also rowed for the King's College Second Eight in 1935 alternating at position 5 with W.M. Colles (left).



Two works which influenced his thinking are outlined here and immediately below.






The Jevons Machine (left) constructed in Victorian times is described below.





The Logic Machine devised by Turing protégé Dietrich Prinz (above).


As mentioned above, Alan M. Turing was elected a Fellow of King's College, Cambridge in 1935 at the age of only 22.

'On Computable Numbers', published the following year, was his most important theoretical work.

It is often said that all modern computers are Turing machines in hardware: in this single article, Turing ushered in both the modern computer and the mathematical study of the uncomputable.

During the early stages of the war, Turing broke German Naval Enigma and produced the logical design of the 'Bombe', an electro-mechanical code-breaking machine. Hundreds of Bombes formed the basis of Bletchley Park's factory-style attack on Enigma.

In 1945, inspired by his knowledge of Colossus, Turing designed an electronic stored-program digital computer, the Automatic Computing Engine (ACE).

At Bletchley Park, and subsequently, Turing pioneered Artificial Intelligence: while the rest of the post-war world was just waking up to the idea that electronics was the new way to do binary arithmetic, Turing was talking very seriously about programming digital computers to think.

He also pioneered the discipline now known as Artificial Life, using the Ferranti Mark I computer at Manchester University to model biological growth. Turing went to work at Manchester University in 1948 after leaving the National Physics Laboratory where he had pioneed the Pilot ACE computer described on the next page.

In 1949, Turing's protégé, Dietrich Prinz, worked with philosophy lecturer Wolfe Mays to devise the electrical relay-operated symbolic logic machine pictured above.

Built from RAF spare-parts, the machine is a device for testing logical propositions.

Turing was fascinated by thinking machines and, in 1950, wrote a paper published in 'Mind' that contained what would become known as the 'Turing Test', a way to measure machine intelligence.

This early Enigma machine with just three rotors was the first on public display having been donated by GCHQ (the British Government successor to Bletchley) in 1980s.

Enigma, used in the twentieth century for enciphering and deciphering secret messages, was invented by the German engineer Arthur Scherbius at the end of World War I.

Early models were used commercially from the early 1920s, and adopted by military and government services of several countries and most notably by Nazi Germany before and during World War II.

German military texts enciphered on the Enigma machine were first broken by the Polish Cipher Bureau, beginning in December 1932. This success was a result of efforts by three Polish cryptologists, Marian Rejewski, Jerzy Rozycki and Henryk Zygalski, working for Polish military intelligence, using a prewar bombe method.

From 1938 onwards, additional complexity was repeatedly added to the Enigma machines, making decryption more difficult.

On 25 July 1939, in Warsaw, the Poles initiated French and British military intelligence representatives into their Enigma-decryption techniques and equipment. The intelligence gleaned from this source, codenamed 'Ultra' by the British, was a substantial aid to the Allied war effort.

Though Enigma had some cryptographic weaknesses, in practice it was German procedural flaws, operator mistakes, laziness, failure to systematically introduce changes in encipherment procedures, and Allied capture of key tables and hardware that, during the war, enabled Allied cryptologists to succeed.

The exact influence of Ultra on the course of the war is debated; an oft-repeated assessment is that decryption of German ciphers advanced the end of the European war by two years.

Bletchley Park Manor 2003 - Administration, Offices etc. in wartime (above).

Hut 8 at Bletchley Park in 2003 (above). Note the partly demolished anti-blast walls.


Turing is widely associated with Bletchley Park during the war years and hence the title of this exhibition, 'Codebreaker'. For a time he led Hut 8 (pictured above), the section responsible for German naval cryptanalysis.

Turing devised a number of techniques for breaking German ciphers, including improvements to the pre-war Polish Bombe method.

Development of the Bombes was conducted in Hut 11. Details will be found on the Bletchley Park website: the link is shown at the top of the page.

Each of the rotating drums simulates the action of an Enigma rotor.








The rear of a Bombe machine under reconstruction reveals a vast number of interconnecting wires (right).

Hundreds of bombes formed the basis of Bletchley Park's factory-style attack on Enigma.





A Bombe during reconstruction (above and left).

There are 36 Enigma-equivalents and, on the right-hand end of the middle row, three indicator drums.

A guide explains the working of the Bombe in 2003 (below).

For more details about Bletchley Park please click on the link at the top of this page.


THE NEXT PAGE (Part 2) includes further details of Alan Turing's life, the Tunny and Colossus Machines and Turing's Pilot Ace (Automatic Computing Engine) Computer.

Please click on the 'Next Page' link below right.

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