A rare surviving Enigma machine that almost undid the heroic efforts of the Bletchley Park codebreakers in World War Two is tipped to sell for £100,000. The German machines had three rotors, each with 26 positions, to create 17,576 possible combinations for each letter.
It was used by the Nazis to code and decode secret messages which were considered 'unbreakable' until British mathematicians led by Alan Turing were famously able to decipher it in 1942. In response to this alarming development, the German Luftwaffe issued an 'update'.
They introduced a field rewirable reflector, called the UKW-D, to the machine, making their messages even more secure and threatening to outpace Turing's breakthrough. But the UKW-D was not invented until 1944, meaning it was not widely distributed before the war's end and failed to turn the tide in Germany's favour.
