In his book on the Lucan affair, Trail of Havoc, Patrick Marnham made one of the most vivid calculations in modern British biography. Lucan, he explained, was a very unadventurous eater. In his days as a house player at the Clermont Club, his taste ran to nothing but smoked salmon and lamb cutlets. The latter were grilled during the cold months and served en gelée in warmer times. Marnham therefore estimated: ‘If Lord Lucan ate four lamb cutlets a day, for four days a week, for eleven years, and if there are seven cutlets in a sheep, then he would have despatched 1,007 sheep.’

Patrick Marnham is excellently placed to write well about Simenon: he has forensic, journalistic and francophonic expertise. But an additional qualification must be a small numerological kink. Simenon’s life is pungently studded with figures like