Their mission: to crack the Nazi Enigma cypher. The odds against them were a staggering 150,000,000,000,000,000,000 to 1. Their success in breaking this seemingly 'unbreakable' code was one of the greatest intellectual achievements of the twentieth century.
By March 1946 they were all gone, removing every scrap of evidence of their codebreaking exploits as they left. Their efforts in breaking those 'unbreakable' codes in the utmost secrecy caused Winston Churchill to coin the phrase "the geese that laid the golden eggs and never cackled". It would be decades before Bletchley Park would start to reveal its secrets.
By 1991, the Park was deserted, its buildings facing demolition. The Bletchley Park Trust was formed with the aim of preserving the site for posterity. So began a long and arduous campaign. The Trust fought off hostile bids from property speculators and waded through a mountain of Government red tape to clinch a deal that saved Bletchley Park for the nation.