‘I have the feeling’, confides Richard Cathar, the hero and narrator of Justin Cartwright’s eccentric new novel, Lion Heart, ‘that I have strayed into genre fiction.’ His suspicion is correct. This long, diffuse, improbable narrative dallies with a series of popular forms that might strike some as unexpected choices for the distinguished, Booker-shortlisted author. The book moves from Dan Brownish conspiracy thriller to espionage drama, Francophile romance to social satire of the broadest type (a lecherous tutor named ‘Edgar Gaylard’; an uninspiring lawyer named ‘Derek Cocks’), never quite settling on any particular tone. It is nothing if not unpredictable.

Cartwright crams his pages with incident. Richard is the orphaned son of a Sixties dropout, a spliff-addled amateur historian so obsessed with Richard the Lionheart and the Third Crusade that he christened his child after the monarch and changed his surname from Carter ‘when he was at Oxford in 1963