We don’t think of Christie as a political author. Perhaps we should. Her views, though, may not make for cosy Sunday viewing. The buzz of anti-Semitism is loud in her fiction of the 1920s, with its references to “Hebraic people” and “yellow-faced financiers” – and this is more than the thoughtless transmission of cultural background noise. Christopher Hitchens, who had dinner chez Christie in the Sixties, recalled “the anti-Jewish flavour of the talk was not to be ignored or overlooked, or put down to heavy humour or generational prejudice. It was vividly unpleasant.” Should a mainstream documentary ever be brave enough to tackle this job, they should recall Suchet. Who would be better qualified than the son of a Jewish Lithuanian immigrant; a man who has spent a quarter of a century waxing Poirot’s moustache? Then, perhaps, we might solve the real mystery of Agatha Christie – how her work became so ubiquitous, and so unexamined.