Mutton begins with 46-year-old Clara Hutt, India Knight's fictional alter ego (and heroine of her previous novels My Life on a Plate and Comfort and Joy), making a list of all the things she's started doing "due to age". These include making an "Oof" sound when she sits or bends; noticing the "dreadful acoustics" in restaurants; and suffering from two-day (sometimes three-day) hangovers. Causes for most alarm, though, are the laughter lines around her eyes, her slipping eyelids and the frown line running across her forehead. She may own Louboutins, "kickass underwear", and tight dresses, but builders, she realises, no longer wolf-whistle at her in the street.

Cue Clara's attempts to navigate the choppy waters of female middle-aged cliches. Her friend Gaby's had enough work done to pass as a 15 years younger, "really hot cartoon" version of herself; then there's Annie, "mutton, pure and simple", sequins, leathery decolletage and a trowel-load of slap, but still sexy with it; and finally, 43-year-old Alice, who dresses "like a granny" (baggy beige cardy and sensible flat shoes) and is appalled by the idea of fishnet tights. Clara occupies the middle ground, until, that is, envious of Gaby's wrinkle-free forehead, she decides to give Botox a go.

Bernard, the "beardy weirdo" who writes insanely popular fantasy fiction, and is the father of Clara's 19-year-old son's girlfriend, is a refreshing addition to the cast. Not least because all the women calling one another "darling" and chatting "divorcey hideousness" like overgrown schoolgirls definitely begins to grate after a while. Knight's trademark sharp-tongued wit appears in flashes, but overall the story feels a bit tired. The message may well be that Clara is still in her prime, but as a heroine she's past her sell-by date.