The Enigma machine was an encryption device used in all branches of Nazi Germany’s military during World War 2. Former World War 1 codebreaker Dilly Knox was convinced he could break the system and set up an Enigma Research Section, comprising himself and Tony Kendrick, later joined by Peter Twinn, Alan Turing and Gordon Welchman. They worked in the stable yard at Bletchley Park and that is where the first wartime Enigma messages were broken in January 1940.
But Channel 5’s ‘How Britain Won World War 2’ documentary revealed how there was another, even more secretive code used by Adolf Hitler’s highest-ranking men.
Presenter Michal Buerk explained: “The real crucial theatre of war was to the east, in Russia.
“From the very beginning, [Sir Winston] Churchill knew that by helping Russia, we would be helping ourselves.
“British codebreakers unravelled a secret so powerful that Stalin used it to smash Hitler’s invasion of the Soviet Union.”
British genius Bill Tutte broke the code
The Lorenz SZ42 proved difficult to break
The documentary explained how a code nicknamed ‘Tunny’ had left the team at Bletchley Park stumped.
Military historian Dr David Kenyon said: “If you think of Enigma as a tweet, then Tunny was more of a long email.
“The second difference is who is using the system, Enigma was used by the Army and Navy, whereas Tunny was used by very senior Germans communicating with each other.
“It was a level of secrecy above Enigma.
“If you read one Enigma message, it doesn’t tell you a great deal, but a single message from a senior commander could be very powerful.”
READ MORE: Churchill’s worst-case defence plan for Nazi invasion of UK mapped in astonishing detail
Military historian Dr David Kenyon
Mr Buerk detailed how a breakthrough soon came from the team.
He added: “This is the machine that sent the code, it’s called a Lorenz SZ-42 and there are only four left in the world. It makes Enigma look like a child’s toy.
“Enigma used either three or four rotors to turn a message into a scrambled stream of letters.
“The Lorenz, on the other hand, had 12 rotors.
“Unlike Enigma, the Lorenz codebreakers had no captured machine to help them, but an unknown young maths whizz took on the challenge.
Tehran’s war capability revealed amid tensions with West [ANALYSIS
US soldier risked ‘cataclysmic outcome’ with defection to USSR [COMMENT]
Turkey close to Russia’s grasp amid Trump fury after Venezuela ruling [ANALYSIS]
William Brutte played a key part in the war effort
“In 1941, a mistake by a German radio operator enabled Bletchley Park to decipher one message from the complex code and 24-year-old Bill Tutte took a go.”
William (Bill) Tutte was a British-born Canadian codebreaker and mathematician who noticed a pattern in the messages being sent.
Presenter Arthur Williams explained: “Using nothing more than a pencil and paper, Tutte finds that pattern, he realises that the opening 12 characters of every message are not part of the message.
“They were instructions for creating the secret code. One letter for every rotor on the machine.”
Churchill past the information on to Stalin
The breakthrough allowed British intelligence officers to decipher long messages on German war plans on the Eastern Front.
Sir Winston called for it to be sent across to Joseph Stalin as he fought off a Nazi invasion.
Using the intelligence, the Red Army prepared an almighty counter-attack in Kursk, in what became the biggest tank battle in history.
It led to a crushing German defeat and is remembered as a key battle in the Soviet victory in the east.
‘How Britain Won World War Two’ will be shown on Channel 5 tonight at 8pm.