The work at Bletchley Park is said to have shortened the war by two years
A woman from Glastonbury has been honoured by the Prime Minister for her work at Bletchley Park during the war.
Thelma Moeran recently received a badge and a certificate signed by Gordon Brown.
Bletchley Park was home to more than 10,000 men and women during World War II, whose job was to decode messages sent between German forces.
The cracking of the codes, and the resulting action by the Allies, is said to have shortened the war by two years.
Thelma Moeran was involved in the interception of messages from Germany and the U-Boats, which were then passed on to Bletchley.
She was stationed at an underground unit in Scarborough during her work, which she has never heard of since.
Thelma spoke to BBC Somerset's Emma Britton about her life working in the secretive world of Bletchley.
"The day-to-day work involved listening o German and Italian Morse code stations," she said.
"We had done some very intensive training prior to this work and we had to be able to read Morse code accurately at 25 words a minute.
"That was very difficult to achieve [and] that took months and months of training, to not make any mistakes writing at that speed."
BLETCHLEY PARK FACTS
Bletchley park is found 50 miles (80km) north-west of London
In 1883, it became home to the Leon family, whose patriarch was a wealthy City of London financier
Herbert Samuel Leon bought over 300 acres of land beside the London and North-Western Railway line that passed through Bletchley
Mr Leon developed 60 of those 300 acres into his country estate
At the heart of the estate, he built a mansion in a mixture of architectural styles
One of Bletchley's greatest benefactors, Mr Leon was much loved by the local people and was awarded a baronetcy in 1911
During World War II, Bletchley Park was the site of the UK's main decryption establishment - the Government Code and Cypher School
Bletchley Park is also known as Station X
The high-level intelligence produced at Bletchley Park, codenamed Ultra, provided crucial assistance to the Allied war effort
Bletchley Park is now a museum, run by the Bletchley Park Trust, and is open to the public
Everything that Thelma and the other Bletchley workers picked up was in code, so they had no idea what they were intercepting.
"There were types of messages," she added.
"There was a message called a 'B Bar' which meant that they were going into attack.
"It took a third of a minute for them to send, so there was no relaxing - you could not relax when you were on duty."
Thelma said the people who recruited her and her co-workers were "very selective" and that they almost "weeded out" the people who they wanted to join the Bletchley staff.
And Thelma admits that she had no idea what she was applying for when she answered that job advert.
"I had no idea what work we were going to do," she added.
"We weren't given any idea - we were simply told that we'd be shot if we were ever caught because we were spies.
"The whole thing was exciting in a way but boring in a way too, being chained to a radio for hours and hours."
Thelma stayed in the UK until Victory in Europe (VE) Day and was then sent to out to Sri Lanka, where she was involved in the interception of messages from the Japanese during the war in the Far East.
She was 21 years of age and it was the first time that she'd ever left the country.
Now, Thelma works with crystals in Glastonbury, has a second home in Arizona and also attends church with two other women who also worked at Bletchley.