The story of the breaking of the Lorenz machine – more complex and secure than Enigma – in the words of the man who broke it.

The breaking of the Enigma machine is one of the most well-known stories of the Second World War. But there was another German cipher machine used by Hitler himself to convey messages to High Command and his top Generals in the field.

The Lorenz machine was vastly more complex and secure than Enigma. For 60 years no one knew about Lorenz or 'Tunny' due to the utmost secrecy surrounding it. No one knew about the courageous group of brilliant people who finally broke its code. From victory at the Battle of Kursk to the success of the D-Day landings, Lorenz decrypts helped to shorten the war in Europe by several years.

Here for the first time, the late Jerry Roberts reveals how these forgotten heroes of Bletchley Park achieved their staggering, statistically impossible achievements, and how he tried to get better recognition for his fellow codebreakers.