Colossus World War 2 Code Breaking Computer

GCHQ releases unseen images of WW2 code-breaking computer

Colossus World War 2 Code Breaking Computer

The Government Communications Headquarters (GCHQ) in the UK has released previously unseen photographs of Colossus. The images are being released to celebrate the 80th birthday of this World War 2 code-breaking computer.

It was created during the Second World War to decipher messages between senior German generals in Europe. It remained a secret for six decades before its existence was finally revealed in the early 2000s.

Colossus World War 2 Code Breaking ComputerColossus World War 2 Code Breaking Computer

GCHQ says that Colossus “played a pivotal role” in the war. It confirmed the receipt of disinformation during the D-Day landings in Normandy. Engineers working on the device were sworn to secrecy, with eight of the ten Colossus machines being destroyed once the war was over.

Those that remained were kept in service until the early 1960s as the technology was so effective at its job. It is considered by many to be the first digital computer ever created.

Colossus World War 2 Code Breaking ComputerColossus World War 2 Code Breaking Computer

One rare photograph was accompanied by the above letter. GCHQ says that it tracks “the progress of the work being done to decipher communications between senior Nazis”. The letter also references “Flowers of the P.O.” and the machine that would eventually become Colossus.

Another section of the letter describes some “rather alarming German instructions” that had been intercepted during the previous two weeks.

Colossus World War 2 Code Breaking ComputerColossus World War 2 Code Breaking Computer

A former GCHQ engineer, Bill Marshall, says that he worked on Colossus during the 1960s. He’d just signed the Official Secrets Act and didn’t really have much of a clue what he would be doing. He says he was told little about the machine he was working on.

It was his job to attempt to repair any issues that popped up without knowing how the entire thing worked. He had just a few circuit diagrams and no user manual.

Colossus World War 2 Code Breaking ComputerColossus World War 2 Code Breaking Computer

The development of the Colossus machine was a huge advancement in Bletchley Park’s codebreaking efforts helping the Allies break one of the most complex ciphers of WWII. Thanks not just to Colossus, but the pioneering post-war computing work of codebreakers like Alan Turing, Max Newman, Donald Michie, and Jack Good, Bletchley Park is considered a birthplace of modern computing.

This legacy was key in Bletchley Park being chosen as the host venue for the world’s first Artificial Intelligence Safety Summit in November 2023.

Colossus was more than two metres tall and contained over 2,500 valves in its construction. Many consider Colossus to be the birth of modern computing and the first digital computer.

You can find out more about Colossus on the GCHQ website.

[Images: Crown Copyright/Open Government License]