AN insight into how the German attack on merchant shipping during the Second World War, known as the Battle of the Atlantic, was countered by Ultra code-breaking intelligence will be given by naval historian and author Jock Gardner at Haslemere Hall on Monday.

Mr Gardner also wrote a book on the subject of his talk for Haslemere U3A, ‘The Battle of the Atlantic and Ultra Code-breaking’, which starts at 2pm. The author served in the Royal Navy for nearly 30 years, working as a specialist in anti-submarine warfare.

Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park.

The intelligence received made a very significant contribution in the Battle of the Atlantic.

Winston Churchill wrote: "The only thing that ever really frightened me during the war was the U-boat peril."

The decryption of Enigma signals to the U-boats was much more difficult than those of the Luftwaffe. It was not until June 1941 that Bletchley Park was able to read a significant amount of this traffic and transatlantic convoys were then diverted away from the U-Boat ‘wolfpacks’, and U-Boat supply vessels sunk.

Admission to the U3A talk is free and non members are welcome.