The Duchess of Cambridge’s grandmother Valerie Glassborow and her twin sister Mary were among the codebreakers stationed at the top secret base at Bletchley Park during the Second World War.
The crack team, which also included famed British mathematician Alan Turing, of researchers and cryptographers was tasked with intercepting and interpreting enemy communication and breaking the German enigma code.
Enigmas, which resembled large typewriters, were used by German air, naval and army forces to safely send messages throughout the Second World War.
It used a complex series of rotors and lights to encrypt messages by swapping letters around via an ever-changing ‘enigma code’. The code was eventually broken in 1941 by mathematicians at Bletchley – a feat that proved a crucial turning point in the war.
Valerie Glassborow and her twin sister Mary worked in Hut 16 at Bletchley Park. She later married Peter Francis Middleton (pictured on their wedding day) and had four sons, Michael, Richard, Simon and Nicholas. Michael is the father of the Duchess of Cambridge
Two women work in hut 6 at Bletchley Park, Buckinghamshire, during the Second World War. Cryptographers deciphered top-secret military communiques between Hitler and his armed forces, which ultimately aided the victory of the Allied forces
Then a young, unmarried woman, Valerie Glassborow worked in Hut 16 on the estate, which is no longer standing.
Many of her colleagues were ‘ordinary’ middle-class women like herself, whose work, kept secret for almost half a century, helped change the course of the war.
However very few went on to pursue a career in intelligence. Indeed of the 9,000 people who worked at Bletchley Park during World War II, just 600 women went on to join the fledgling GCHQ or other branches of the secret services.
Among those to leave the service for a life of domesticity was Miss Glassborow, who married Peter Francis Middleton in 1946 in the village of Adel, Yorkshire.
The couple went on to have four sons, Michael, Richard, Simon and Nicholas in quick succession.
Michael, the eldest, is the father of the Duchess of Cambridge and is known to have been close to his mother.
Miss Glassborow died in 2006, without ever speaking publicly of her wartime service.
A black and white photo offering a look inside one of the huts on the Buckinghamshire estate. Among the roughly 9,000-strong workforce was Valerie Glassborow, the paternal grandmother of the Duchess of Cambridge