The submarine in a ‘vegetable patch’: Code in letters sent home by British PoW in WWII to help Allies is revealed after 70 years.
- ‘My Dear Mummy’: Even start of Sub Lt John Pryor’s letters signalled code
- Pryor was captured at Dunkirk in 1940
- Mathematicians and military intelligence experts crack MI9 code
- Coded words alternated between every fourth and fifth word and also involved fiendish alphanumeric key
- Contained hidden requests for maps, passports and currency as well as war intelligence.
The letters sent back home by Sub-Lieutenant John Pryor from a German prison camp seemed innocent enough. They often started with ‘My Dear Mummy & Daddy’ and talked about mundane things such as gardening and a ‘vegetable patch’. But the British wartime letters actually contained hidden messages, which have only now been deciphered by academics. It is also the first time the captured serviceman’s family has been able to understand the secret messages.