Code-cracking secrets of Bletchley Park shared at Hornchurch Library
18:00 15 June 2014
The secrets of code breaking were revealed during a not so secret talk by a member of the Bletchley Park Trust last week.
Second World War anoraks, maths whizzes and puzzle experts turned up to Hornchurch Library in their droves for a D-Day inspired event hosted by Tom Briggs,
Armed with a real enigma machine, he demonstrated how staff at the top-secret base cracked German codes, which is thought to have helped cut the length of the war by two years.
“It went really well,” said Tom, who used to run code-cracking classes as a Maths teacher. “They were a really good audience, really responsive.
“I gave them some codes to decipher while I spoke to them, Some rose to the challenge, and some didn’t. Adults can get a bit defensive about it, but some of them absolutely love having a go.”
The machine, an electro-mechanical device which scrambles a plain text message into ciphered text, was invented by a German engineer at the end of the First World War and adopted by the German Navy and Army in the 1920s, and the German Air Force in the 1930s. It was also used by the railways and other government departments.
Bletchley Park, a stately home 40 miles north of London, was used as the base for a group of scientists, mathematicians and chess-masters to intercept and break the codes.
In May 1938, admiral Sir Hugh Sinclair, head of the Secret Intelligence Service (MI6) bought the mansion for use by Government Code and Cypher School (GC&CS) and SIS in the event of war.
One of the most famous names to work there was Alan Turing, who led Hut 8, responsible for decrypting the German naval Enigma, and developed the bombe, a refinement of a Polish cipher-breaking machine, named the cryptologic bomb.
“He is the one everybody knows,” said Tom. “But there were about 10,000 people working there who did just as much work, like Gordon Welchman [who developed an advancement to Turing’s bombe].
Tom also spoke abou the Battle of the Atlantic, when the Bletchley Park team were faced with cracking an “unbreakable” cipher developed by the German naval engima.
After retrieving data from the German U-Boat, U-110, in May 1941, the code-crackers were able to read German communications and re-route convoys around the U-Boats, whose position they had learned. Merchant ship losses dropped by more than two-thirds as a result of their work.
The fascinating tales captured the imagination of the 90 plus people in attendance at the North Street library, with many staying behind for an in-depth question and answer session.
“I didn’t think I was ever going to get to leave,” joked Tom. “They were really interested. There were so many questions, it was really good.
“You go to some talks and there’s one or two questions but at Hornchurch it wasn’t like that. It makes you feel like you have done your job properly.”
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