2.5(ish).

Somewhat dry Poirot pastiche is Sophie Hannah's fifth in nine years, and it lurches through a series of slowly drip fed clues until it reaches a conclusion that is almost insulting in its contortions. Featuring psychology that would absolutely not fly today and would have likely been a stretch for Christie even back then, it is often too ridiculous to contemplate.

If a huge part of your reveal hinges on a visual clue that the reader literally can't see and the narrator can't be expected to interpret, if our friend Poirot and his little grey cells are withholding, that seems to break so many of the commandments of detective fiction that Hannah should be kicked out of the club.

This was read for festive flair, but it lacked elan of any variety. Fortunately there are approximately 47 legitimate Christie Poirots out there, so grab one of them instead.