Spokeswoman Laura May Sivers said: “If you enjoyed the hit film The Imitation Game starring Benedict Cumberbatch and Keira Knightley, you’ll love this evening learning about the exceptional Alan Turing and his Enigma machine that helped win World War II.

“This Mark Baldwin broadcast is one of the most compelling stories of World War II, of the Allied codebreakers who deciphered vast numbers of secret German messages and used the intelligence thus gained to hasten Allied victory. .

“The Germans had entrusted their secret communications to an ingenious encryption machine, the Enigma, which was portable, easy to use and could be configured in millions of ways. Codes were used and each was changed every 24 hours.

“This fascinating lecture features the life and work of the great mathematician, computer scientist, philosopher and theoretical biologist Alan Turing.

“The Allies gained invaluable information on troop and aircraft disposition, orders of battle, U-boat movements, technical development, military intentions, and tank and artillery strengths. Intelligence from Enigma is generally believed to have shortened the war by about two years.

“Mark Baldwin has made a detailed study of the Enigma machine, the decoding work at Bletchley Park and the U-boats and has put together a unique collection of slides which illustrate the main features of these important facts of World War II. You can expect to hear an entertaining educational program on this subject.

“The show is divided into two parts. This is followed by an opportunity for questions and then a hands-on demonstration of one of the very few surviving Enigma machines that are so rare.

Royal Hippodrome Theatre, Saturday 20 August, 7.30 p.m.

Tickets £19 at the box office on 01323 802020 or​​​​​​