Photos: WWII codebreakers return to Bletchley Park
The 70th anniversary of work that helped fight the Nazis
During the Second World War these women pictured helped crack the codes used by the Nazis to protect communications.
On Sunday these women and more than 100 other veteran codebreakers returned to Bletchley Park, where in 1939 the British began to decipher German military code which was created using the Enigma coder.
The reunion event coincided with an exhibition of more than 70 vintage cipher machines at Bletchley, which have been gathered from museums, private and government collections around the world.
At the event the wartime staff saw the enemy Enigma machines, whose coded messages they had worked so hard at to decipher, for the first time.
Photo credit: Bletchley Park
During the World War II, Bletchley Park was a codebreaking factory. By the end of the war the site employed 12,000 people, who worked in shifts to break the thousands of communications that were being intercepted each day.
Messages from the German, Italian and other hostile countries were intercepted by a web of wireless intercept stations around Britain and sent to Bletchley. Workers were split into groups, who worked in huts decoding army, naval, air force and intelligence communications.
As well as cracking codes, staff carried out a range of other tasks, from translation of the original messages to pinpointing where the communications had been issued from.
Electromechanical machines such as Bombe and Colossus played a key role in cracking the codes, automating much of the laborious mathematics needed to decipher the messages.
Colossus was the first machine to break the Lorenz - a complex cipher machine used to pass important messages between the German army field marshals and their central high command in Berlin.
The Colossus is one of the first ever programmable computers and can be seen up and running at Bletchley Park after a major restoration programme.
Photo credit: Bletchley Park
The intelligence produced by messages decrypted at Bletchley contributed to Allied success in destroying the German U-boats that patrolled the Atlantic, and to British naval victories in the Battle of Cape Matapan and the Battle of North Cape.
Many of the veterans returning to Bletchley on Sunday were the Royal Navy Wrens who worked on the Type-X and the Bombe machine, developed by mathematician Alan Turing to crack the keys to Enigma codes - which the Germans would change on a daily basis.
A spokeswoman for Bletchley Park said: "It is beautiful listening to them talk about what they did and really brings home the reality.
"One of the ladies who had worked on the Bombe machine showed how she used to take off the cylinder rotors to change them.
"Others talked about how they had to wear stilettos to work on these tall machines or told how they had to strip off in the summer because these machines generated such a lot of heat."
She said that many of the staff were unaware of the full extent of the codebreaking that took place at Bletchley Park and only knew about the work that went on in the hut they worked in.
Bletchley Park recorded audio and video of the workers' recollections and museum staff plan to exhibit these after the museum at Bletchley is revamped.
The museum is currently applying for a grant from the Heritage Lottery Fund to finance a redesign.
Photo credit: Bletchley Park