Sitting was Katherine Parkinson's debut play, adapted for TV by BBC Lights Up, a remarkable collusion between telly and theatres throughout a land-in-the-days-of-Covid: there will be 18 in all, featuring such writers as Colm Tóibín and Frances Poet, and mesmerising themes for our times. And it just goes to show that an enterprise can be worthy, valuable - and yet gleefully witty and poignant.

There were surely influences of Alan Bennett behind the overlapping monologues of three "sitters" for a portrait, but the tone overall was singularly Parkinson's. The story was simply told: the sitters, faced with silence, slowly begin to gab away to the unseen artist, and are thus revealed, early, simplistically, as Luke (Mark Weinman), a wife-hating sad man with daddy issues; Cassandra (Alex Jarrett), a wannabe actor and pathological fantasist; and Mary (Parkinson), a fading mistress with distressing sibling memories.

The overlapping of direction, with some voices cutting in and cutting off, some on triptych split-screen, the intercuts of monologue ("She's really getting through the Rennies at the moment"/"I absolutely love sex"), all against the same drab studio curtain, leads you to thoroughly believe it's all contemporaneous and unrelated. Which just leads to slow, eye-widening shock as the final 10 minutes reel by. A triumph, not only for the writer: Weinman and Jarrett also convince with consummate skill. Presumably, with BBC Four about to end commissioning of new content - without it we wouldn't have, say, Charlie Brooker, or Detectorists - this has just scraped in under the wire, and I can't tell you how glad I am, nor just how much the corporation is skittering away its own pearls.

Sitting, BBC Four, review

Katherine Parkinson's play veers from humorous to quietly shattering.