I’ve been a member of the Times of London Crossword Club three weeks now, mostly to get the weekly Listener crossword. The three new ones since I’ve joined have been relatively easy (for Listener crosswords, that is). But yesterday I worked on the crossword from January 16, which is called “Conversion”, and it’s more the crazily difficult puzzle I associate with the Listener. The instructions are bewildering, to start with:

In 18 clues, the definition has undergone a conversion and contains a single misprint that must be corrected before solving. In clue order, the correct letters give a thematic introduction. All answers must be amended prior to entry; the across answers according to the part of the introduction given by down clues, and vice versa. These include two entries that are clued without definition, both of which are professions that were found wanting.

On locating the subject of the puzzle in the grid, solvers must carry out a conversion (the source of which was itself a conversion). This completes, in the shape of the subject’s place of work, a thematic quotation that must be highlighted.

The clues were pretty tough, with a lot of obscure words involved, and it took a good while before I had enough pairs of crossing answers to come up with a hypothesis about how to enter them to make the crossings work. Fortunately my guess was pretty close to being right, and once I could enter words in the grid and get help from the crossings, things started falling into place more quickly. The breakthrough came when I had finally enough of the 18 changed letters to figure out the first half of the “thematic introduction”. I didn’t know the phrase, but I googled it and that told me what the theme was. Figuring out the significance of the two “professions that were found wanting” narrowed down the subject of the puzzle, which indeed was located in the grid — it was startling to realize that it had been staring me in the face, really. That made it clear what was meant by all the uses of “conversion” in the instructions, with a nice unexpected surprise at how many different but perfectly appropriate twists of meaning it had.

And then the final surprise was finding the “thematic quotation” in the nearly completed grid (I still had a few unsolved clues in the upper left corner). Not a particularly short quotation, either. It could not have been easy for the setter to construct the grid, what with all the limitations: (a) the subject being hidden in the grid, (b) the quotation being hidden in the grid, (c) the across and down answers being modified in accordance with a phrase that is appropriate to the theme of the puzzle, and (d) the whole thing still having to work as a valid crossword puzzle grid with the right numbers of crossings in all the words. Just amazing, a wonderful piece of work and a very tough and satisfying puzzle to solve.