Code breaking at Bletchley Park
8 March 2010
I left school in 1939, aged 15. My mother had had surgery and the war had started – I wasn’t interested in school. Then when I was 18 I volunteered to join the Navy. I was sent to train at Tullichewan Castle on Loch Lomond. After a bit they told me I would be sent to London, and it was secret. ‘We can’t tell you what you will be doing there because we haven’t been told.’
First I was at Eastcote, Middlesex, for training and then Outstation Adstock before being posted to Bletchley Park itself, working on the Bombe. Bletchley Park is one of the main code-breaking centres of the Second World War. It’s where the Enigma code was cracked.
The Bombe was an electro-mechanical machine made up of 36 Enigma machines. There were around 200 Bombes, and they were staffed by WRENs. There were two of us on each machine, and three watches a day, so there were about 1,600 girls in all. We lived in nearby villages. There were ten to a room in my first house. Then I was moved to Woburn Abbey, and we were bussed in each day to Hut 11.
We set up the 108 drums on front of machine and wired up the back according to a menu prepared by the people in Hut 6. The Bombe cracked the German Enigma settings by running through millions of different options. We never knew what was successful – it was all very secret and the possibilities each time were 158 million million million to one. But the Germans did silly things, like always sending a weather forecast at a particular time of day, and that helped the codebreakers.
Mathematician Alan Turing was the brains behind the Bombe. I never met him, but I did meet Doc Keen, who built it at the British Tabulating Machine Company at Letchworth. He was a brilliant man. Morale at the factory was low, so some us of went there to give a talk. There were lots of women working there as well.
After Bletchley Park, I was sent to Ceylon (now Sri Lanka) to do code breaking by hand. I worked on meteorological data from captured Japanese documents. Knowing the weather conditions was very important to our ships and aircraft.
I didn’t want to go overseas – I thought my father would oppose it, but he said in the war I should do my bit. I met my husband there and that my father did oppose that! But my mother brought him round.
I went to Bletchley Park reunions many years later, and after my husband died I trained as a volunteer guide. It makes such a difference for the visitors, talking to someone who was actually here during the war. And this year I’m on a training course with John Harper who rebuilt the Bombe. All the original Bombes were destroyed at the end of the war, and the course is fascinating. We are going to do lots more practical demonstrations, and I will be able to answer some of the really technical questions we get.
I’ve thought a lot about why they chose me to work at Bletchley Park, and I think its because on my application I put that I was good at crosswords! I still do the crossword each day even now.
Jean Valentine is a volunteer guide at Bletchley Park, the National Codes Centre near Milton Keynes.