De-coding the messages sent using the Enigma machine by code breakers at Bletchley Park enabled the allies to decode German radio signals.

The work at Station X was top secret and it's only recently we've begun to find out how important it was to the outcome of the war.

The Jersey War Tunnels has an Enigma machine but the attraction had to call on the services of Tony Sale, a Bletchley Park expert to make it work properly.

Where did this machine come from?

60,000 of the machines made. It may be possible to find out whether it's an army or air force machine. This one at the Jersey War Tunnels is probably mid-war time in age, probably made in 1942 or 1943.

How does it work?

The German encoder had a setting sheet which told him which rotors to put in the machine and which order - so he assembled those into the machine. Then he would have to make the plug connections on the patch panels at the front. He would then have to set the ring settings on the wheels when they were in place in the machine. He'd rotate those to an offset given on the setting sheet.

Now, he would encipher his message by pressing down the letters of the message and writing down which lamps light up. That was then given to a radio operator who transmitted them by morse-code.

At the other end, the operator had the same setting sheet so he configured his Enigma machine to exactly the same configuration.

Then he keyed in the enciphered text, and the message came out on the sequence of lights

How was it de-coded?

The problem for the Allies was to read the messages,. They needed to break the cipher. The problem was the vast number of combinations - something like 150,000,000,000,000 combinations of possible configurations of the Enigma machine!

The Germans thought it was impossible to break the cipher system. But it was the human errors, the silly mistakes the Germans made in their operating procedures which gave the clues which enabled the code breakers at Bletchley Park to break the machine and de-crypt the messages.

The Germans changed the settings every day at midnight, but at Bletchley Park, they eventually reckoned they hadn't done very well if they hadn't sussed it out by 3am the same morning!

Click on the links provided for detailed information on how the codes were broken, and remember, you can now see a working Enigma machine here in Jersey.