Counterfactual history in the novel is usually the domain of genre fiction. Len Deighton’s SS-GB (1978) presents a Britain conquered and occupied by a victorious Nazi Germany and Robert Harris’s Fatherland (1992) opens in the week before Hitler’s 75th birthday. D J Taylor’s 11th novel, The Windsor Faction, charts a similar alternative history, albeit one that revolves around Germany’s militaristic intentions in 1939. Taylor’s what-if premise is set out in the prologue: what if Wallis Simpson had died in 1936 and Edward VIII had never abdicated? The parallel world Taylor creates is charged with tension but also rich in period detail and thick with multifaceted characters, which elevates it from straight generic adventure to shrewd literary thriller.

The novel is itself a book of factions, formed from a number of disparate strands. If there is a lead character it is Cynthia Kirkpatrick, who, upon returning from Ceylon with her parents, finds London on a war footing. She starts work at a new literary magazine. During a weekend