Colossus Supercomputer Altered WWII Course

British Government Intelligence Department (GCHQ) Reveals Details about Colossus, World’s First Electronic Digital Computing Machine

For the first time, the British government intelligence department, GCHQ, has disclosed information about Colossus, the world’s first electronic digital computing machine. Colossus was created during the Second World War to hack the encryption of the German command and played a key role in the victory over Germany.


Despite its historical significance, the existence of Colossus remained a secret until the 1980s. It was only 20 years ago when the participation of this machine in World War II was officially confirmed. The disclosure of information about the computer not only shed light on the events of wartime but also required a revision of the history of computer technology. Some of its characteristics are still classified, showcasing its remarkable advancement for its time.

Colossus was a bulky machine, standing at 2 meters high and containing 2500 radio lamps. A total of 10 such computers were constructed, with the first one becoming operational on February 5, 1944, and the second on June 1 of the same year, possibly on the eve of the Normandy landing.


The main task of Colossus was to hack the advanced ciphers used by the Commander-in-Chief of Germany, enabling the allies to receive real-time information about the German General Staff. Notably, Colossus confirmed that Hitler believed the allies’ misinformation and expected a landing in Pas-de-Calais, rather than on the beaches of Normandy.

Declassified images include photos of the computer itself and the women from the Women’s Royal Naval Service (WRENS) who served it. The level of secrecy surrounding Colossus was so high that these women had no knowledge of the purpose of the machine or the techniques used to operate and maintain it.


A published letter mentions Tommi Flawers, an engineer of the British postal service and the chief designer of Colossus. He designed the computer based on components from the telephone station. Additionally, a page with the Colossus schematics has been made available for enthusiasts interested in its inner workings

/Reports, release notes, official announcements.