Setters and solvers yesterday gathered at Bletchley Park, the heritage site of the British decryption establishment, in recognition of the puzzle’s role in the recruitment of codebreakers.

Professors, mathematicians, linguists, graduates were all famously headhunted once to pit their wits against the Nazis, but so too were avid crossword fans.

Seeking citizens with the brains and the tenacity needed to break the German Enigma codes (the most famous of the cipher systems to be cracked at Bletchley Park), a newspaper competition was set up challenging readers to solve a crossword in under 12 minutes.

It was, of course, just one of many methods. However, unless Sudoku is given an unexpected role in the battle against climate change, it is tempting to claim that never was so much owed by so many to such a fiendishly addictive phenomenon.

Initially, there were only a couple of hundred people working on the top-secret codebreaking missions at Bletchley Park, but thanks to a recruitment drive, in which the crossword played its part, there were almost 9,000 based at the Buckinghamshire site by 1941.

It was The Daily Telegraph of London that set the crossword challenge.

“I always thought it was strange, if they wanted to recruit the best minds, they went for The Telegraph rather than The Times,” teased Richard Browne, who confessed his less than partial view as Times crossword editor. “Then again,” he added, “it was possible all The Times crossword solvers at the time were already working at Whitehall.

“They weren’t necessarily looking for the most brilliant people, but the good puzzle solvers who were prepared to stick at something and see it through to right to the end. They wanted people with the right attitude.”

The puzzles have flourished in the Internet age, added Browne, with entire online communities built on the shared passion of cryptic clues.

“They seem as popular as ever, and will probably remain so for another 100 years,” Browne said.

Not bad for a game that began life as a hurried way of filling the pre-Christmas “fun” pages of a New York newspaper.

Arthur Wynne, the Liverpool-born editor of the games section of the New York World, called his diamond-shaped grid “word-cross” but for some reason, it was reversed on publication.

Readers became hooked. By 1924, the puzzle prompted such mania that The Times New York correspondent, Louis Hinrichs, reported on America’s “enslavement” to the black and white grid, calling it an “insidious pastime”.

“Crossword puzzles,” he lamented, “have dealt the final blow to the art of conversation and have even been known to break up homes.”

The next year, a certain Koerner, stuck on the last clue, became so frustrated that when his wife refused to help and went to bed, he followed her upstairs and shot her. She survived. He didn’t — later shooting himself.

A year later, a waiter in a Budapest cafe killed himself. Why, no one knows — he wrote his suicide note in crossword form but no one could decipher it.

Despite such tragedies, the puzzle’s popularity grew. Simon & Schuster began by selling crossword compilations.

The Times finally relented in 1930, initially requiring its erudite readership to produce answers in Latin and Greek. In November 2011, the newspaper published its 25,000th crossword.

Browne, the crossword editor, speculated that it was unlikely that the Bletchley codebreakers would have been seen frowning over crosswords, during breaks in their long shifts. “There probably wasn’t much time for crosswords. Lives were at stake. Or maybe relaxing with a crossword was a bit too much like work.”

Ian Standen, chief executive officer of Bletchley Park, said that many veterans often referred to their aptitude for crosswords as one of the reasons they passed the selection process.

He points to the example of a veteran, who recently returned to Bletchley, where she worked on a cipher as a Wren. “She was given calculations to do. She didn’t know what it was for. She just did them for eight-hour shifts and passed them on. It was that dogged determination, that application and attention to detail they were looking for.”

He was speaking at an event hosted by the publisher of Puzzler, the magazine. Crossword fans from as far as Hungary and France joined the event, which involved setting their own Enigma-theme cryptic crossword, under the guidance of John Halpern, a broadsheet crossword setter.

Halpern, who describes himself as “someone who looks at a menu and sees ‘desserts’ as ‘stressed’ backwards”, said it was wonderful to think that, in their own small way, crosswords “helped to save the world”.