It is rare to find a piece of theatre that handles the issue of dementia with just the right balance of comedy and gravity. More unusual still is a sensitive portrayal of septuagenarians by a twenty-something playwright. Yet Visitors triumphs in both respects: it is a compassionate portrait of a wrenching disease and Barney Norris’ first full-length work.

Visitors centres around an elderly couple, Edie and Arthur, still happily married on a small farm in Salisbury. The first scene is crucial for establishing the tender dynamic between the pair. Propped up in their armchairs, they reminisce about a holiday in Dorset and ponder what else they could have been (Edie is clear: a despot!). Soon the audience gathers that Edie is the early stages of dementia. In fact, the day on which the play opens is a turning point: a carer is moving in. Both Arthur and Edie seem acutely aware that Edie’s condition will only deteriorate.

The young carer, Kate, is warm and instinctive – though not without troubles of her own. She stands in contrast to Arthur and Edie’s son, the cold, bland metropolitan Stephen, who turned his back on the family farm many years ago. Father and grandfather tilled the fields: Stephen works in life insurance. Stephen has never got on with his parents and swiftly plans to put Edie in a home. An initially unsympathetic character, the generous script gradually encourages us to see what he lacks. He has his health (for now), but not the type of bond that exists between Arthur and Edie. They have each other.

Visitors is not showy, not flashy. It moves us through words and clever human insights (Edie bravely tries to keep up with the latest recipes, attempting something called ‘falafel’). The performances are superb – particularly Linda Bassett as Edie. Sometimes her expression alone captures all the pain of a woman plunging into fog. The sitting-room setting is perfect for the intimate North Wall theatre. Small plays making us think about big issues is what this theatre does so well. The only shame is that this play is itself a visitor, staying just one night in Oxford. Look out for it touring again – and keep an eye on writer Barney Norris.