A walk through life inside Britain's WWII codebreaking hub...
Seventy years ago inside drab huts in the heart of Buckinghamshire, British codebreakers unpicked the secret communications of the Nazi war machine.
The work of the World War II codebreakers based at Bletchley Park allowed the Allies to stay one step ahead of the German military.
Today it was confirmed that the Bletchley Park Trust will receive £4.6m from the Heritage Lottery Fund (HLF) to create a new visitors' centre on the site - seen here during the Second World War - and renovate the huts where the codebreaking took place.
CEO of the Bletchley Park Trust Simon Greenish said the award recognised the site's role in history.
"Bletchley is getting a lot of recognition and quite rightly so because this is arguably one of the most important sites in 20th-century Britain," he said.
silicon.com spoke to Greenish about why the work that took place at Bletchley was so important, what life was like for the codebreakers and the site's role in developing one of the world's first electronic computers.
The German army, navy and airforce protected their communications using a encryption machine called Enigma, which turned regular German text into gobbledygook.
Every day the German military would change the settings they used to encrypt messages and each day the Bletchley codebreakers were engaged in a race against time to crack that day's code.
"The real victory at Bletchley was their ability to find their way into the communications of hundreds of groups [within the German military], every single day during the course of the war. They were in there usually within four hours, sometimes less," said Greenish.
"Once you had got the Enigma wheel settings you could read the messages as fast as the German officers."
To help crack Enigma, a team of mathematicians led by Alan Turing developed the electromechanical Bombe machine in 1940, which can be seen above. Each Bombe was built to work as if it were several Enigma machines wired together and was able to narrow down the settings used to encrypt each message far quicker than a human could. By the end of the war Bletchley was using 220 of the machines to crack codes.
Bletchley was also home to one of the world's first electronic computers, Colossus. Colossus was developed to help automate the cracking of the Lorenz code that protected the communications between Hitler and his High Command. Colossus reduced the time it took to crack Lorenz from weeks to hours, as it was capable of working through the 1019 different ways that Lorenz could garble messages far more quickly than a person.
Greenish said that were it not for Bletchley supplying intelligence on the movement of German U-boats that the Nazis could have cut Britain's vital transatlantic supply line.
"The shipping convoys were the lifeblood to Britain," he said.
"The war could have easily have been lost had it not been for Bletchley, as during the early part of the war the only way for convoys to avoid U-boats was to know where they were."
As the war progressed technology was developed that allowed the Allies to sink German U-boats, allowing the Allies to use Bletchley's intelligence to pinpoint and destroy the German submarine wolf pack.
Despite their heavy U-boat losses, Greenish said the Germans could not conceive that the Allies had cracked Enigma, as they failed to grasp that Bletchley codebreakers had figured out the workings of Enigma and had found a way to automate codebreaking.
"Codes were being broken on regular basis. [But] the Germans kept coming back to these huge numbers [of ways of encrypting messages using Enigma] and saying you cannot deal with them," he said.
Pictured is the main manor house at Bletchley Park.
Personnel within Bletchley worked in isolated cells - with groups of codebreakers, translators and intelligence analysts working independently of each other in different huts.
"Because they all worked in compartments many of them were not aware of the import of what they were doing," Greenish said.
"The all knew they were codebreaking but they didn't know the impact of all of this, they had no idea until 30 years later what the importance of the collective work really was."
Huts were staffed by a mix of men and women - a high proportion of whom were Navy Wrens - and by the end of the war Bletchley's workforce was about three quarters women.
Staff worked round the clock, in three eight hour shifts. Conditions inside the huts would have been pretty unpleasant, Greenish said, as the huts' thin, uninsulated walls meant they were cold in the winter and hot in the summer.
"The working conditions were by today's standards pretty crude but the people who worked there would say they were pretty lucky because they weren't in the firing line," said Greenish.
Today, Bletchley Park attracts about 140,00 visitors each year, and has seen its visitor numbers more than triple over the past five years.
Greenish, who can be seen here stood outside Hut 6 in Bletchley, said the HLF investment will help Bletchley cope with its rising popularity.
"The expectation is that we could get as many as 250,000 visitors a year and we need a new visitors' centre, shop, toilets and facilities to cope with the sheer volume of people," he said.
"This investment is the key - it gets the site sorted out to cope with visitors, puts the infrastructure in place and the majority of exhibitions. This allows us to go forward and gives us the long-term economic future that we need."
The cash will help restore the huts and the grounds to what they would have looked like at the peak of Bletchley's operations during World War II, complete with props and costumed staff.
The Bletchley Park Trust needs to raise another £1.7m of match funding before it can access the HLF money and begin work on the site. Greenish said he expects the trust will have the funds it needs by next year and will complete the work by 2014.
Bletchley's profile has rocketed of late, with the Queen unveiling a tribute to the codebreakers in July and Bletchley personnel issued with medals in 2009.
The Heritage Lottery Fund has already given Bletchley Park £460,000 to fund restoration work.