Bill Who? The Lesser Known Codebreaker of Bletchley Park

The work of Bletchley Park during the Second World War is inspirational-numerous codes were broken and incalculable lives were saved. It is important to remember that code breaking at Bletchley Park was a team effort and not something that one person could have achieved alone. However, some people are prominent due to their unique contribution; Bill Tutte was one of those people.
W. T. (Bill) Tutte

W. T. (Bill) Tutte

“Bill who?” Is the standard response I receive whenever I mention his name. If I’m lucky, then the person to whom I am speaking has heard of Bletchley Park and Enigma, and if it is a really good day then they have heard of Alan Turing; but it is rarely the case that they have heard of Lorenz, Colossus, Bill Tutte or Tommy Flowers.
A Naval Enigma Machine

A Naval Enigma Machine

So let me clarify. Alan Turing cracked the Enigma code as used by the German Army, Navy and Air Force. It was a cipher transmitted via Morse code and was an important tactical code to break. The breaking of Enigma is widely remembered for its significance when tackling U-boat threat during the Battle of the Atlantic. When we talk about Tutte, Flowers and Colossus, this is in reference to the Lorenz cipher-an enciphering attachment to a teleprinter machine. Lorenz was used by the German High Command, so a break into Lorenz revealed the strategy of Hitler and his generals-highly significant communications during World War Two.
Lorenz SZ42

Lorenz SZ42

So what was Bill Tutte’s contribution to the breaking of Lorenz?
Very simply, Tutte deduced the structure of the Lorenz cipher through analysis of two pieces of cipher text where the original messages had been enciphered using the same settings, but with slight differences between the texts (e.g abbreviations and misspellings). This meant the encipherment could be removed and then Tutte could look for recurring patterns within the text, eventually deducing the entire structure of the machine. This enabled Tommy Flowers to design and build Colossus, the world’s first digital computer, which was used to break the Lorenz cipher. Tutte’s achievement has been described as the greatest intellectual feat of the Second World War, because unlike Enigma, Tutte deduced the structure of Lorenz with no information about the machine or what it looked like.
Surely that deserves a memorial?
Author: Claire Butterfield

23 responses to “Bill Who? The Lesser Known Codebreaker of Bletchley Park

  • Neil Calkin

    Thanks for posting this. He was a great (and extremely modest) man, who to the end refused to talk about his work during the war.

  • Steve Martin

    Great summary, the story of Bill Tutted and Tommy Flowers deserves to be much more widely known.

  • mcfontaine

    A brilliant man who deserves to be known so much more than he is now.

    I produce The Bletchley Park Podcast and when we interviewed Bill’s wartime colleague Captain Jerry Roberts earlier this year, as always he spoke of Bill’s amazing feat of breaking “Tunny”.

    Good luck & let me know if there is any way I can help.

    Mark Cotton / mcfontaine

    • May Roberts

      Thank you warmly, Mark, great support of Bletchley Park (BP), we really much appreciate it. You have done so much to help BP voluntarily!
      Mark Cotton is a musician, his website:

      For more about Bill Tutte, Tunny and the Testery, herewith a website BBC Timewatch programme about the Tunny story titled: ‘Codebreakers – Bletchley Park’s Lost Heroes’: This programme won two BAFTAs Awards of 2012, for the best documentary. And an international award in Jan 2013.

  • Nog Sawdon

    Yes, Bill does deserve recognition. My father, a brilliant German-speaker, also worked on the Enigma Code at Bletchley Park, and they all were an absolutely magnificent team of incredibly bright men and women. I am so proud of him.

  • Paul Niland

    Sounds worthy of a memorial to me! Thanks for this blog, picked up through the RT of @ProfBrianCox

  • M Crilly

    Truly a great man. Thanks for bringing him to our attention.

    For the record, Alan Turing didn’t really break the enigma code per-say; it was in fact the Polish who broke it first. See this link for details:

  • Sivaram

    and a minor nitpick that no one mentions the Poles contribution to the Bombe that Turing continued to work to make it more general.

  • Alice Wonderland

    Captain Jerry Roberts, former senior cryptographer at Bletchley Park from 1941 to 1945. Jerry is the last survivor of the 9 codebreakers who worked on Tunny (the Lorenz cipher), Tunny-system broken by Bill Tutte in Spring 1942. Capt. Roberts worked same office as Bill Tutte.

    Tens of thousands of Tunny messages were intercepted by the British and broken at Bletchley Park by Captain Jerry Roberts and his fellow codebreakers in the Testery team, where the real Tunny message breaking happened.

    There were two major cipher-systems worked on at Bletchley Park during WW2 – Enigma and Tunny. Tunny was Hitler’s most secret code system and had 12 wheels against well-known 3 wheels Enigma. Tunny was only declassified 10 years ago compared with Enigma in 1970’s. Tunny carried only the highest grade of intelligence: messages between German Army H.Q in Berlin and High Command to the top Generals and Fieldmarshals on all key battle fronts. Many messages signed by Adolf Hitler himself.

    Enigma decrypts helped Britain not to lose the War in 1941.
    Tunny decrypts helped shorten the European War by at least 2 years.

    The information provided by Tunny enabled the Allies to ascertain German movements, saving millions of lives at critical junction such as D-Day and the battle of Kursk in the Soviet Union. Gen. Eisenhower (later U.S President) said that “Bletchley decrypts shortened the War by at least 2 years”. Tunny decrypts played a vital part in this – a war which was costing more than 10 million lives a year. A great deal of this was down to Bill Tutte and the Testery by Cbreaking of Tunny messages. If the D-Day landing had failed, it could have needed at least 2 years to prepare for another major assault.

    Why is the work of Bill Tutte, Tunny and the Testery still so little known?
    Unlike Enigma, the work on Tunny was declassified only a few years ago. Most of the Tunny cryptographers had died before they could tell their stories.

    If Bill Tutte had not broken the Tunny system, if the breaking of Tunny messages had not been so vital, there would have been no need for a Colossus (computer) at that time.

    For the last 5 years (at age 92 now) Captain Roberts has been work hard to get better recognition for his colleagues in the Testery and for Bletchley Park “Heroes” – 4T’s (Tutte, Tunny, Testery and Tommy Flowers), and for their achievements, which still remains to be told properly. The Testery did the real Tunny message-breaking 90%, it has received little recognition for Tunny as whole.

    Please spread the word about Tunny, Bill Tutte and the Testery, if we can!

    For more story about Tunny and Bill Tutte, watch the BBC Timewatch programme:
    Titled: ‘Codebreakers – Bletchley Park’s Lost Heroes’

    Also Captain Jerry Roberts’s UCL talk in 2009 is online:

  • John Jozwiak

    Alan Turing didn’t crack the Enigma code, but Marian Rejewski and other Poles did, if I remember, but Turing figured out how to automate the necessary process so that recracking, as the codes shifted, was computationally feasible faster than the codes were shifting.

  • billtuttememorial

    Thank you for all for your comments. The Polish were crucial in providing the initial break into Enigma in the early 1930’s and credit is due Marian Rejewski, Henryk Zygalski, Jerzy Rozycki and their colleagues for their contribution. However, due to refinements of the Enigma cipher, the methods devised by the Poles were no longer viable by late 1938 so improved methods had to be developed by those working at Bletchley Park. As stated in the blog, code breaking was a team effort and even Alan Turing’s bombe needed refinement by Gordon Welchman. All those involved in the code breaking effort deserve to be remembered. This blog was intended as a basic comparison of Enigma and Lorenz during the war; the Polish contribution was not deliberately omitted.

  • Alice Wonderland

    Tunny and Enigma is completely 2 separate cipher system!

    Bill Tutte who broke 12 wheel Tunny and he had never seen the machine, Tunny helped shorten the War by at least 2 years. Tutte was a real hero at Bletchley Park for Britain and for Europe, and he never got any reward of any kind, or recognition.

    Alan Turing broke 3 wheel Enigma, he had at least seen the machine. He’s contribution was breaking Naval Enigma in 1941, so saving Britain from not losing the War. Turing was another hero for Britain!

    Yes, Polish did broke Enigma earlier on, but only Air and Army at most, but not all the system used by the Germans.

  • pete bailey

    Should be better known. Been to Bletchley Park many times. Wel . Well explained there.

  • Metrader

    This man 92 Captain Jerry Roberts, recognition for Bill Tutte tirelessly 5 years is on twitter: ‏@Wonder88 – and 755 followers only since September 2009.

    meanwhile, Gangname style gets more than a billion……

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  • Jeanne Cullen

    Metrader, you are spot-on. “Codebreakers – Bletchley Park’s Lost Heroes” should be required watching for every student, and any person who wants to get a more complete picture of WWII. You will get the story from an amazing man who was there, Capt. Roberts. At 92, this brilliant, eloquent, humble patriot knows what he’s talking about. Enigma is only a part of “the Codebreakers” story. On Veterans Day in the U.S., we need to honor the contribution of every codebreaker (from the Poles, to the Brits, to the Navajo Marines). IF anything good can ever come from war, the team effort at BP to defeat Hitler is a shining example. We can never forget the atrocities inflicted upon millions during WWII; let us honor the few who were key to stopping those atrocities.


    When I read that only 18 responses were recorded , I felt that three naughts should be added to he 18 at least. It is a pity that there was so much secrecy attached to the project. At least he had the most important aspect of it , in that he had the personal satisfaction and sod the rest of them. In memory of a genious.
    John D. Crisp

  • RichardLH

    “For more story about Tunny and Bill Tutte, watch the BBC Timewatch programme:
    Titled: ‘Codebreakers – Bletchley Park’s Lost Heroes’ ”

    The BBC have taken that down now (from YouTube anyway). The UCL one is still there though and worth a look for the modesty and humour with which it is delivered.

  • willisk

    I believe the Kryptos sculpture has the story of BletchleyPark in it. K3 as the section is called by the Kryptos Group, describes King Tuts tomb being broken into. I believe this is a TRIBUTE to TUTTE’s 1+2 Break-in. Another line deciphered in Kryptos states, IT’S BURIED OUTHERE SOMEWHERE> Information Technologies buried. The British supposedly buried Colossus (Tutte/Flowers) and the totality of Bletchley Park, BURIED IN HISTORY. and only seeing the light of day circa 1990. The Greatest Achievement of WW was performed by a Chemist and Intellectual Giant. Dr Tutte and Mr Flowers were denied Greater places in Acknowledge history than they deserve.
    I had NEVER heard of Colossus/Tunny/Bletchley Park until I started working on the Kryptos sculpture, and the story is in the letters of the sculpture.. This led me to BP..and onwards ONLY the BEST TUYA

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