Iola and Anest are septuagenarian twins, born seconds apart (or, as their long dead father would have it, found in a lobster pot) and, it seems, determined to die together now that Iola’s dementia has reached the point where she no longer wants to live.

In a mix of the poetic and the mundane,whimsical family folklore is interspersed with scenes of the messy practicalities of dealing with a loved one who is losing her mind.

Hamish Pirie’s sensitive, often funny production shows the complex emotions surrounding an all too common situation, here given added poignancy by the closeness of the twins, umbilically bound till the end.

Anna Calder-Marshall (Iola) and Anna Carteret (Anest) shine lovingly as the devoted old ladies, the former delightful on a good day, violently aggressive when things get bad, the latter starting to show occasional ominous signs of deterioration, too.

Imogen Stubbs is also affecting as Anest’s daughter, arriving on a mercy dash from Bristol but beset by problems of her own (including an unseen phobic husband whose neuroses feed her own obsessive compulsive disorder) even before Iola brews her mobile in the teapot.

There’s nice work, too, from Roger Evans as Gareth, local policeman and old friend trying to bring some supportive sanity into a household where things are going from bad to worse.

Trafalgar Studios (2), Whitehall, SW1A 2DY
0844 871 7632
Until December 3
Tube: Charing Cross
£17.50 – £22

– Louise Kingsley