The surviving workers from the Bletchley Park cryptography unit are to be honoured, nearly 70 years after the unit was formed.

The Bletchley Park code breakers, known as Station X during the Second World War, were never officially recognised for their invaluable work in deciphering German, Italian and Japanese military codes – work this is thought to have shortened the war by more than two years and saved millions of lives.

All staff were banned under the Official Secrets Act from even discussing the location of their military service until the 1970s and the site itself was nearly dismantled in the interests of secrecy. Winston Churchill called the staff "my geese that laid the golden eggs and never cackled".

Now, at long last, military and civilian workers will receive a special commemorative badge from the government in recognition of their vital war work.

“These people made an enormous contribution to the outcome of World War Two, the 20th century and freedom in the West,” said Simon Greenish, director of the Bletchley Park Trust.

“After many years of having to keep their critical wartime work top secret, it is tremendous that this contribution has finally achieved recognition.”

Heroes of Bletchley included Tommy Flowers, who built one of the world’s first programmable computers, Colossus, largely using his own funds, and Dr Alan Turing, who designed the bombe cryptanalysis machines.

Flowers received an MBE and an award of £1,000 for his work while Turing was arrested for homosexuality in 1952 and committed suicide shortly afterwards, having received no official recognition for his work in his lifetime.

Foreign secretary David Miliband said: “I am delighted that the vital and secret work of Bletchley Park in the Second World War is being recognised.

“We owe a debt of gratitude to all who served at Bletchley Park and its outstations. I am proud to acknowledge their ingenuity, skill and determination, which helped our country in its time of greatest need.”