I was mildly startled to note that, until a fortnight ago, these pages had not covered one of the most intriguing episodes in crosswording: the D-day codewords enigma.

While choosing which information, apparent information and theories to include in telling the tale, I wondered momentarily if I was short-changing its protagonist: Leonard Sidney Dawe, the setter who was visited by MI5 to find out why his puzzles contained so much information about the most secret of top secrets. I was indeed. As reader Jolly Swagman remarked:

It's a shame that L S Dawe's name only ever comes up in this context. He was one of the [Telegraph]'s leading setters and [probably] one of the key figures in the evolution of cryptic crosswords in UK dailies.

Let's put that right.

The Daily Telegraph was one of the first British newspapers to embrace the American novelty of the "cross-word puzzle" in the 1920s; indeed, it was the effect on the Telegraph's sales that persuaded the Times, after a period of sniffiness bordering on hostility, that there might be something in this wordplay business after all.

Nor was the the Telegraph itself overly keen: that paper already had a contributor of acrostics, who said he would not touch crosswords "with a bargepole". In her profiles of pioneering setters, A Display of Lights, former Telegraph puzzle editor Val Gilbert is puzzled as to how the first setter was then recruited, presuming that it was word of mouth which suggested that the chaps for the job might be found at St Paul's School: classics master Melville Jones and science master LS Dawe (later known by his pupils as "Moneybags", via his pre-decimal-currency LSD initials).

The acrostician's disrelish is understandable: the form of the crossword was still evolving and the task of the first Telegraph setter was to create a variant that the readership would come to find addictive, without their knowing quite what it was on first sight.

That first setter was Dawe. He later described his first puzzle, from 30 July 1925, as "ghastly". That's a little harsh: yes, clues like "conjunction" and "pronoun" are underwhelming and "military abbreviation" is downright grim, but the puzzle itself is to be cherished, if for nothing other than the decades of British broadsheet crosswords which followed.

It was during Dawe's watch that the crossword became a more satisfying challenge, adding more black squares, losing filler words and two-letter entries, and eventually indicating the wordplay more cryptically than boldly stating "(hidden)" or "(anag.)".

Along the way, Dawe experimented with themed puzzles (Val Gilbert's book reproduces a 1927 grid based around doctors and dentists) and rhyming clues; more than that, he should be remembered for the sheer volume of his output: in 1961, he reckoned that he'd written over 5,000 Telegraph puzzles, and he had a couple more years in him.

That spot of unpleasantness with the D-Day codewords, then, is best seen as a curious incident which occurred when Dawe had already been setting for two decades, or when he had two decades' more setting to come.

Others may remember him for his brief footballing career, or depict his war years in the form of a prog-rock concept album, but today we toast Leonard Dawe for taking the crosswording clay of the 1920s and sculpting us something magical.