During World War II, the best brains in Britain cracked Germany's encrypted secrets but never broke their own code of silence.
Now gray-haired and using walking sticks and at least one wheelchair, the legendary code breakers returned for a reunion on Tuesday at Bletchley Park, where they labored in the grim, blacked-out rooms and played a key role in defeating the Nazis.
The code breakers who worked here in anonymity helped alter history, frustrating Adolf Hitler's ambitions by giving Prime Minister Winston Churchill and his wartime Cabinet crucial advance knowledge of Germany's invasion plans, defenses, and U-boat movements.
Age has not dimmed the code breakers' fierce pride. They don't boast, the British don't do that, but they know they saved lives. "Do you know what Churchill called us?" said Jean Valentine, 84, her blue eyes flashing. "He called us 'the geese that laid the golden eggs but never cackled."'
Tuesday's event was to honor a rebuilt replica of the Turing Bombe, the machine invented by mathematician Alan Turing that was an outsized forerunner of the modern computer. That invention deciphered the Germans' top-secret messages that were encoded by the Nazis' typewriter-like Enigma machines.
"It was like getting a newspaper of German material every day," said Andrew Hodges, author of a biography about Turing. "The war would have been very different without it."
The real heroes were the hundreds of mathematicians, cryptographers, crossword puzzle aficionados, chess masters and other experts who spent their days and nights operating the machines at Bletchley Park, about 40 miles (65 kilometers) northwest of London.
They knew they would be targeted by waves of German bombers if word of their location leaked. That never happened, although three bombs did land nearby. It is believed the target was a nearby train station, not Bletchley Park itself.
Their work provided crucial information in the Battle of the Atlantic, the desert campaign against German Field Marshal Erwin Rommel and the preparations for the D-Day invasion of France. For decades after the war, they were prohibited from talking about their top-secret work. But those restrictions began being lifted in the 1970s, allowing them to tell their friends and family what they had really done during the war.
Finally, the geese could truly cackle, but traditional British reserve kept them from saying too much.
"We really didn't know what we were doing other than breaking German codes," said Valentine, a teenager during the war. "You weren't supposed to ask questions. You weren't supposed to know what was in the messages. No one knew anything about what anyone else was doing. It was strictly compartmentalized."
The sense of accomplishment came, she said, when a supervisor would say "Job up." That meant they had managed to decode another message for the military.
"That gave us enormous satisfaction," Valentine said. The pleasure was fleeting, however, because there was always another message waiting to be decrypted. The job was never finished, until the Nazi regime collapsed.
Ruth Bourne, 83, said the lifting of secrecy rules has allowed many of the code breakers to finally learn how important the operation truly was at a time when Britain's very existence was threatened.
"We've researched and found out an enormous amount about how important this was," she said. "Now I feel much more excited about it than I ever did when I was working on it."
The secret activities at Bletchley Park provided the setting for the 2001 romantic thriller "Enigma," which starred Oscar-winner Kate Winslet, as well as other movies and spy novels.
The focus Tuesday was on fact, not fiction, and on the real lives shaped within these walls. For many, the reunion and the rebuilt replica of the Turing Bombe brought back a flood of memories. All the Turing Bombe machines were destroyed after the war on Churchill's orders, because of security concerns, but the replica has been painstakingly rebuilt, a process that took 13 years. It was briefly switched on Tuesday, turning back the years.
"It's a pleasure to see the machine because that is my wife's legacy," said retired Brig. Patrick Erskine-Tulloch, 90, remembering his wife, Peggy, who died six years ago. "She was an instructor and taught dozens of ladies how to use that machine. It was my wife's big thing in life, even though she always played it down."
He credits two people for the success of the code-breaking operation: Churchill, for his determination, and Turing, the early computer whiz.
Erskine-Tulloch endorses the widely held view that the success of the Bletchley Park code breakers saved an untold number of lives by hastening the Allied victory.
"The great thing is that the Germans never realized we'd broken their code," he said. "Otherwise they would have done something about it. They thought it was unbreakable."