First Class Colossus Stamp

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Colossus veterans welcome recognition of overlooked hero Tommy Flowers

Royal Mail honours Tommy Flowers with a first class Colossus stamp

Veteran Colossus operators are delighted with the recognition of Colossus, the world’s first electronic computer, and its designer Tommy Flowers in the latest set of stamps issued by Royal Mail.

Royal Mail’s Inventive Britain stamp issue celebrates eight key inventions of the past century in disciplines and applications ranging from materials to medicine. One of the two first class stamps in the series celebrates Tommy Flower’s creation of Colossus. The series is released on 19 February 2015.

Colossus, the world’s first electronic computer, was designed by Tommy Flowers to speed up the code-breaking of Lorenz-encrypted messages between Hitler and his generals. The Lorenz cipher was much more complex than Enigma and could take weeks to decipher by hand. By reducing code-breaking times to a matter of hours, Colossus enabled the Allies to learn of German war plans almost in real time. The knowledge obtained is widely recognised to have shortened the war and saved countless lives.

A working reconstruction of Colossus and the story of the breaking of Lorenz can be seen daily at The National Museum of Computing on Bletchley Park.

Two of the very first users of Colossus Mk I are delighted with the news.

Irene Dixon, WRNS Service Number 88023, said “I’m absolutely thrilled that Royal Mail is recognising the achievement of Tommy Flowers which was kept secret for so long. In December 1943, I was 19 when I arrived at Bletchley wondering what my secret duties would be. For the next 18 months I was a Colossus operator although I dared not speak freely of this until 1995 when I visited Tony Sale and his team to see them rebuilding Colossus. Tommy Flowers’ invention was fantastic and I’m especially proud of him because he was an East Ender like me!”

Betty O’Connell, who worked alongside Irene Dixon on Colossus Mk 1, said: “I think it’s marvellous that Tommy Flowers is being acknowledged by Royal Mail. It is such a shame that his achievement has been overshadowed because of the secrecy around Colossus for so many decades. If Tony Sale hadn’t been so determined in reconstructing Colossus, I don’t think anyone would know that there were two major ciphers broken at Bletchley Park. So I hope that this stamp will promote the whole story of Colossus and the breaking of Lorenz and help give it its rightful place in history as the pinnacle of code-breaking at Bletchley Park.”

Kenneth Flowers, son of Tommy Flowers, also greeted the news warmly: "My father would be delighted with the recognition of Colossus on a first class stamp. I also know that he would have made it very clear that Colossus was a team effort and that he would have regarded the stamp as recognition of the team's work."

Tim Reynolds, Chairman of The National Museum of Computing, said: “Everyone at the Museum is delighted at the news of the Colossus stamp. We take great pride in playing our part in telling the story of the breaking of the toughest German wartime cipher from intercept to decrypt. Even today the inventiveness of Tommy Flowers’ Colossus is hard to grasp and it is very fitting that it will be represented on a first class stamp seven decades after its development.”

Every day visitors come to The National Museum of Computing to marvel at the story of the breaking of Lorenz, Hitler’s top secret cipher. They learn of the code-breakers in the Testery who deciphered a message which led to a work of genius by Bill Tutte in re-engineering of the then unseen Lorenz machine. Code-breaking continued by hand in the Testery until the arrival of Colossus in the Newmanry in 1944. By finding the start wheel positions of the Lorenz machine for each message, Colossus shortened the code-breaking time for each message from weeks to hours enabling many more messages to be decrypted on close to a real-time basis.

The Rebuild of Colossus is now used in TNMOC’s Learning Programme to inspire students to become the next generation of computer scientists and engineers.

A recording of the sounds of the Colossus Rebuild have recently been made by sound artist and composer Matt Parker and will be deposited in the British Library sound archives.

Notes To Editors

1 Royal Mail

More information on Royal Mail’s heritage can be found at This includes an interactive timeline that traces Royal mail history from the 1500s to the present day:

The Colossus stamp has a particular association with Royal Mail, as it was designed and built by Tommy Flowers MBE, an engineer for the General Post Office (GPO), a precursor to Royal Mail.

2 About The National Museum of Computing

The National Museum of Computing, located on Bletchley Park, is an independent charity housing the world's largest collection of functional historic computers, including the rebuilt Colossus, the world’s first electronic computer, and the WITCH, the world's oldest working digital computer. The Museum enables visitors to follow the development of computing from the ultra-secret pioneering efforts of the 1940s through the large systems and mainframes of the 1950s, 60s and 70s, and the rise of personal computing in the 1980s and beyond.

A pledge by an individual benefactor of £1 million if matched funding is found means that every pound or dollar donated to the Museum will count double. Previous funders of the Museum have included Bletchley Park Capital Partners, Bloomberg, CreateOnline, Ceravision,, Ocado Technology, FUZE, 4Links, Google UK, IBM, NPL, HP Labs, and BCS.

The whole Museum is currently open to the public on Thursdays, Saturdays and Sundays from 12 noon, spring and summer Bank Holidays and increasingly during school holidays. Colossus and Tunny galleries are open almost every day. Guided tours are available at 2pm on Tuesdays. There are often additional opening times for the public -- see the website or the iPhone app for updates. Educational and corporate groups are very welcome and may be on any day or evening by prior arrangement.

For more information, see and follow @tnmoc on Twitter and The National Museum of Computing on Facebook and Google+. A TNMOC iPhone App is also now available from the iPhone App Store.

Media Contacts
Stephen Fleming for The National Museum of Computing
01635 299116

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