Bringing Colossus back to life

Colossus was the first machine to break the Lorenz — a complex cipher machine used to pass important messages between the German army field marshals and their central high command in Berlin.

Lorenz had to be cracked by carrying out complex statistical analyses on the intercepted messages. Colossus could read paper tape at 5,000 characters per second and the paper tape in its wheels travelled at 30 miles per hour.

This meant the huge amount of mathematical work that needed to be done could be carried out in hours, rather than weeks.

Pictured are Nigel Shadbolt, the former president of the British Computer Society (BCS), and Andy Clarke, one of the founders of the Trust for the National Museum of Computing.

The BCS donated £75,000 to keep and develop Colossus in its original location.

Credit: National Museum of Computing