As dismal evenings in the theatre go, Smaller is not offensive – merely slow, obvious and banal. Forgettable, too: even within hours of the performance, I experienced an uphill struggle against the mind’s natural inclination to consign it to immediate oblivion.

Dawn French plays Bernice, an overweight schoolmistress who for 25 self-martyring years has spent all her spare time caring for her increasingly disabled mother. June Watson turns on industrial quantities of life-starved Roman Catholic garrulity and passive aggression as her mama (the biggest role in the play). Alison Moyet is Cath, the sister/daughter who got away to pursue a relatively glamorous career as a chanteuse, with extracurricular dalliances with men, now on the Costa del Naff, now in provincial revivals of such musicals as Oliver! Mum moans at Bernice and pines for Cath; Bernice is intensely jealous of Cath; Cath is more of a failure than they realise.

Smaller means well. It will ring bells for any family where one person does an uneven share of practical care for a disabled and often tiresome relative. We see in detail the whole business of lifting Mum on to a wheelchair and thence to the loo. But at every juncture its author, Carmel Morgan, goes like an Exocet missile for the obvious solution. Too often we see that Cath is singing trash to ninnies, for too long we hear Mum rabbiting on infuriatingly. We can see most of the plot’s few events coming long before they happen.

Kathy Burke directs much the way Morgan writes. Dawn French gives a plucky, likeable, unsubtle performance: I never laughed out loud, but a few times she was funny enough to make my shoulders move in a semi- chortle. There is nothing wrong with June Watson’s performance except her habit of putting the brakes on for the final syllable and (especially) consonant of each sentence, in lines like “take the clipperrrssssah”. Alison Moyet has provided her own dull songs, which she sings with a dreariness that goes beyond Cath’s situation. ★★☆☆☆