The new play by Simon Stephens at the Royal Court, directed by Katie Mitchell, consists of three separate episodes, in which we meet three tenuously linked and very different couples. They are all set within the surrounds of Heathrow, with the sound of aircraft engines intruding on the conversations. So the airport becomes a sinister setting, linked to the title of the play. Wastwater is the deepest lake in Britain, constantly overcast by mountains, so never free of shadows.

 
The play gets bleak, fast. The first couple, a foster mother (Linda Bassett) and son (Tom Sturridge), are the most likeable, but their separate futures look grim. The second act takes place in an airport hotel room. An art teacher and a police officer (Paul Ready and Jo McInnes) are embarking on an affair, which progresses in a dark and uncomfortable way. The final part becomes difficult to take, as various themes develop, such as torture and child abuse. The setting is grim and comfortless and the truly evil female, acted by Amanda Hale, turns out to be a foster child of the first character, worryingly, the only one who keeps in touch with her.

 
This is absorbing theatre, not always easy to watch, but raising questions about the future, as none of the characters here will be comfortable in theirs. The sets, designed by Lizzie Clachan, contribute well to the atmosphere, and the acting is always impresssive.  An unsettling but thought provoking evening.

Wastwater is on at the Royal Court until 7 May. For tickets, visit royalcourttheatre.com