The National Museum of Computing houses the world’s largest collection of working historical computers.

Among our collection is a rebuild of Colossus - a working example of the 10 cryptography code-breaking machines that cracked the secret communications of Hitler during World War II.

The 10 Colossus either disappeared into the security state or failed to survive the war; many of the technical materials were deliberately destroyed.

Gavin Clarke talks to National Museum volunteer guide Peter Hoath about the significance of one particular technical diagram; a diagram drawn years later from the memory of Tommy Flowers - the individual responsible for Colossus.

Got a question about the history of war-time cryptographic or modern electronic computing? Curious about our work and collection? Tweet us with the hashtag: #askTNMOC.

You can also go deeper by joining us in person on a trip to the Museum or by taking a guide-lead virtual tour:
https://www.tnmoc.org/events/2020/10/...

For schools, we offer special remote-learning packages:
https://www.tnmoc.org/remote-learning...

Picture credits:
- Colossus diagram - Tommy Flowers, from "The Design of Colossus" in the Annals of the History of Computing Volume 5 number 3, July 1983
- Tommy Flowers - public domain - reference: https://en.wikipedia.org/wiki/Tommy_F...
- Colossus (rebuild) video at TNMOC - licensed by TNMOC under Creative Commons license: https://creativecommons.org/licenses/...