BLETCHLEY PARK, BLETCHLEY, BUCKINGHAMSHIRE

Bletchley Park comprises a late 19th century mansion of eccentric architectural style that was covertly purchased by MI6 before WWII. During the war the mansion was surrounded by a large number of utilitarian huts, some wood, most of brick and concrete. Many of the huts survive, as does the Mansion, though some wooden huts are now in a perilous state of disrepair. Highly secret communications, cipher and coding operations were based here and so sensitive to the war effort was it, that people based in parts of the site did not talk to others about their work - and did not know what their colleagues were working on. The German Enigma codes were cracked here, using an electro-mechanical machine called a Bombe. The operations remained secret for 30 years but involvement of charismatic and eccentric people of high intelligence - Alan Turing, Max Newman and Dilwyn Knox among them - mean the Bletchley Park story has become internationally recognised for the importance of the site in shortening the War. Without Bletchley-derived intelligence, D-Day would have not been possible and the Atlantic Blockade would have brought the UK to starvation.

Later in WWII, the Colossus machine built at Bletchley succeeded in cracking the even more sophisticated Lorenz German codes and Colossus is hailed as the first programmable electronic computer in the world. The original Bombes and Colossus were dismantled after the war, but scrupulously accurate rebuilds - the product of voluntary labour and huge dedication and some large donations - are now in place in the original huts.