You might think that when a writer who has been called the ‘Cassandra of American letters’ turns her gaze to old age, physical deterioration and death, the resulting novel would be bleak. But if Lionel Shriver had, as she has claimed, ‘an absolute ball writing this book’, then perhaps it’s because she enjoys the dystopian, the dysfunctional and the morbid. ‘I tackle precisely the subjects that everyone yearns to avoid,’ she once declared, and as her latest work of fiction opens, things do seem pretty grim. It’s 1991 and Kay Wilkinson has just returned from her father’s funeral and is drinking a steadying glass of sherry with her husband, Cyril. She is a nurse and he a GP and, although only in their early fifties, they see trouble ahead. Kay’s father had Alzheimer’s; he was needy, unresponsive and impossible to love for ten years before he died. Cyril, contemplating Kay’s dry eyes, argues that ‘for creatures to survive in a state of advanced decay is unnatural’. He feels that eighty is about as good as it gets and suggests they commit suicide together when they both reach that age (Kay is a year younger than Cyril). He has a stash of deadly pills in a soap box in the fridge. Kay ponders, then accepts his proposal and this hilariously inventive tale takes off.

The next twelve chapters throw up a series of parallel universes, each exploring a possible future for Kay, Cyril and their three children. As 2019, the year of Cyril’s eightieth birthday, arrives, arguments over Brexit (that ‘pestilent neologism’) rage. By the time 2020 rolls around and Kay’s eightieth birthday comes,