THE mysteries of how British and American intelligence deciphered German codes - shortening the Second World War by an estimated two years - will be unveiled tomorrow.

Mark Baldwin, who runs a Cleobury Mortimer bookshop, is giving a talk entitled Codebreakers explaining how "brain power" changed the course of history and prevented the collapse of Britain in 1942 when German U-boats were sinking "unsustainable" amounts of allied shipping. Mark Baldwin with the code-breaking device that helped win the Second World War.

And a working example of the ingenious "Enigma" machines, now worth up to £30,000 and originally manufactured by the Germans to create their constantly changing codes, will be on display.

"Enigma has become a symbol of the huge job of intelligence that the British and Americans undertook," said Mr Baldwin, 57, of High Street, Cleobury Mortimer.

"I developed an interest in intelligence about 10 years ago. I like to study it as it uses brain power to shorten wars and not to blow people up."

Mr Baldwin, who bought his machine - of which there are only 12 in public hands in Britain - from Denmark, said the talk will focus on the attempts in 1942 to secretly break the codes being sent to Nazi U-boats depriving Britain of supplies.

The talk is at Stourport's Civic Centre at 7.30pm.

For details of the event contact Mr Baldwin on 01299 270110.