The D-Day Daily Telegraph crossword security alarm refers to an incident in 1944 where D-Day codewords ended up being solutions in several Daily Telegraph crossword puzzles. According to Wikipedia, these included,
- 2 May 1944: ‘Utah’ (17 across, clued as “One of the U.S.”): code name for the D-Day beach assigned to the US 4th Infantry Division (Utah Beach). This would have been treated as another coincidence.
- 22 May 1944: ‘Omaha’ (3 down, clued as “Red Indian on the Missouri”): code name for the D-Day beach to be taken by the US 1st Infantry Division (Omaha Beach).
- 27 May 1944: ‘Overlord’ (11 across, clued as “[common]… but some bigwig like this has stolen some of it at times.”, code name for the whole D-Day operation: Operation Overlord)
- 30 May 1944: ‘Mulberry’ (11 across, clued as “This bush is a centre of nursery revolutions.”, Mulberry harbour)
- 1 June 1944: ‘Neptune’ (15 down, clued as “Britannia and he hold to the same thing.”, codeword for the naval phase: Operation Neptune).
It turned out that Leonard Dawe, who created the crosswords for The Daily Telegraph, was headmaster at a school near a camp filled with US and Canadian troops preparing for D-Day.
There was much contact between the schoolboys and soldiers, and soldiers’ talk, including D-Day codewords, which were thus heard and learnt by many of the schoolboys.
. . .
Dawe had developed a habit of saving his crossword-compiling work time by calling boys into his study to fill crossword blanks with words; afterwards Dawe would provide clues for those words. As a result, war-related words including those codenames got into the crosswords; Dawe said later that at the time he did not know that these words were military codewords.