‘E very part is an education,” says Linda Bassett. “That’s the glory of being an actor. You learn about human feelings and frailty and rottenness. The writer puts their soul on the page, and you inhabit that. I’ve always felt I was a writer’s actor.” She’s not wrong. Never showy, Bassett’s understated magic has enhanced plays by Timberlake Wertenbaker , Wallace Shawn, Ayub Khan Din and, notably, Caryl Churchill, of whom she is a peerless interpreter. “Auditioning for Caryl was enormous, because that got me started on a trajectory,” she says. From Fen in 1983 to 2021’s What If If Only , her disconcerting clarity has suited Churchill’s plays, work that some audiences find forbidding. “They’re not hard to watch,” Bassett protests. We’re chatting at the Young Vic, where Bassett is rehearsing Care by Alexander Zeldin, another exacting author.…