Our verdict: three stars

Carol Morley made a name for herself with Dreams of a Life, a moving documentary about the loneliness of city living and those who fall through society's net.

Here, she makes good on the promise shown in that 2011 film with a strange, beguiling drama set in an all girls school at the fag end of the Sixties.

Small, mousey Lydia (Maisie Williams) is best friends forever with the glamorous, precocious Abbie (Florence Pugh). Abbie has a secret the two girls are desperate to keep, but it is not long before the rest of the school knows, with startling repercussions.

Morley leads her cast, which includes Maxine Peake as Lydia's agoraphobic mother, in some unexpected directions, managing to intrigue and amuse in equal measure.

There are lots of big ideas at work here, and even if the tone ultimately swings too wildly, and the ambition proves too fierce, it is a startling and memorable piece, with a uniformly outstanding cast.

One cannot wait to see what Morley does next.

Grosvenor, February 27 (20.30)