Bomber's Moon (Trafalgar Studios)

Almost exactly one year after first opening in this play at the Park Theatre, James Bolam and Steve John Shepherd are giving two of the most skilful and delightful performances in town, transforming an efficient two-hander by William Ivory (whose screenplays include Made in Dagenham) into something very special about care, trust and friendship.

Bolam's Jimmy is a crotchety Second World War veteran in a Nottinghamshire care-home, eking out his days with memories and fears of the past, re-living his escapades as a tail-gunner with his Zimmer frame serving as both spitfire and cumbersome weapon. Shepherd – best known as Michael Moon in EastEnders – is the brand new carer, David, as stiff and starchy as his brand new white jacket.

Their relationship starts with Jimmy on the front foot, swearing jovially away with the licence of old age, bemoaning his wilting sexuality (and his "sleepy old cock") while educating David in his regimen of pill-swallowing and suppository up-shoving and retreating into bouts of anger, patriotism and nostalgia.

The second act of a two-hour play develops in more surprising directions, with David's back story – his faith, his marriage, his own dark moments – coming into focus in such a way as to redefine the caring and cared-for roles and reveal more common ground between the two men. To say they end up tripping the light fantastic would be to say too much, but uniforms and Cole Porter songs come into it.

In less assured hands, the play might have become corny and, with hindsight, predictable. But Matt Aston's direction, with a design of kitchen cupboards and en suite toilet by Laura McEwen, artfully lit by James Farncombe, is pitched and played at just the right temperature in the smaller of the Trafalgar Studios.

Bolam, such a deft and beautiful actor, has the silken technique to deliver a master class in close contact performance: he both accommodates and transcends the spatial restrictions, playing through and beyond the lines and the audience to create a large-scale character, properly articulated, never muttered. Shepherd takes his cue from this, and Bolam wins as many laughs in his listening and reaction "shots" as he generates with his own timing.

The play operates in the present, and in flashback, with a touch of fantasy and a suggestion of characters reaching out across the generations. Apart from all his other woes, Jimmy has prostate problems and hardening of the arteries; it's being so cheerful that keeps him going – to the loo, mostly.