Pam's work in code-breaking involved the use of "Banbury sheets"
In the late summer of 1939 a team of code breakers arrived at Bletchley Park in Buckinghamshire to begin top secret work that was later credited with shortening World War II.
It also laid the foundations for today's Cheltenham-based intelligence centre GCHQ.
Pam Brewster, who's now 91 and lives near Tewkesbury, was among them. She still has vivid memories of working at Bletchley Park 70 years ago.
She told us how she landed her job as a code-breaker, in 1939 at the age of 21.
"I was a Foreign Office civilian for all the war. My mother had got a job and it was through her in hearing that they were recruiting people in GCCS (Government Code and Cypher School) [whose successor is GCHQ in Cheltenham].
"I had an interview and was accepted. I started working in January 1939 in London. I was working on the very beginnings of the Enigma Code with a man called [Alfred] Dillwyn Knox. "
How much did Pam know about the significance of the code-breaking work she was carrying out?
She said: "I didn't speak German so I didn't know what [the broken codes] said, but we knew it was producing information about movements of troops and later on about movements of ships and convoys and submarines.
"I remember hovering around the hut at lunchtime to see if we'd broken [any codes] and we could get this out, as to what the target for that night's bombing was.
Pam worked at Bletchley Park throughout the war
"So you really felt in on it, as it were. You didn't know actual details of what was happening but you knew for instance when a convoy was on its way to Russia."
Pam recognises that the work she was doing helped to speed up the ending of the war. She told us: "They do reckon it shortened the war by three or four years."
"There was a spell when we were sinking so many U-boats that [Karl] Dönitz, who was the big German admiral, was suspecting that we must be reading them, but Hitler was supposed to be so absolutely adamant that his famous Enigma was safe that he wouldn't have it."
Veterans will be gathering at Bletchley Park this weekend (5-6 Sept 2009) where 70 Enigma machines have been flown in from all over the world to be united with the men and women who cracked their codes 70 years ago.
But Pam will not be among them. She has been back to Bletchley Park three times since leaving but said she has no desire to return once more: "It's so different. You've got to remember it as it was. We used to come out of the railway station and nip up a little muddy track through the back garden. There's now all tarmac and car parks. No, I'm not going back again."
Bletchley Park is also keen to capture the memories of other people who worked there.
They reckon that of the 12,000 people who worked at Bletchley Park during WWII, around a thousand are still alive, most of whom have never told their stories, but cannot be tracked down because records were destroyed due to the secret nature of the work.
So if you worked there during the war, in whatever capacity, The Bletchley Park Trust would love to hear from you.