LONDON — Nobody does implacable like Lesley Manville. That steely resolve she has so peerlessly embodied onscreen (her Oscar-nominated performance in “Phantom Thread”) and onstage (her Olivier-winning Mrs. Alving in Ibsen’s “Ghosts”) has been polished to a glittering, icy-blue sheen in “The Visit, or the Old Lady Comes to Call.”

That’s the full title of Tony Kushner’s very protracted adaptation of the Swiss dramatist Friedrich Dürrenmatt’s 1956 classic, which opened on Thursday at the National Theater in London. And while Jeremy Herrin’s three-and-a-half-hour production suffers from terminal bloat, it is undeniably blessed in its leading old lady, whom Manville shapes as a couture-crafted entity beyond good and evil. When she declares, “I am a myth,” you aren’t about to argue with her.

Manville’s character, Claire Zachanassian, is afforded this spot at the pinnacle of world-warping amorality because she is the richest woman on the planet. And, really, what good is money if you can’t use it to get even with those who have done you wrong?

And so Claire, after many years and many husbands, journeys back to the squalid little town — called Slurry, in Kushner’s version — that rejected her as a pregnant, unwed 16-year-old. She has come expressly to get a bit of her own back, which means reclaiming, and destroying, one Alfred Ill, the lover who abandoned and denied her all those years ago (played here by a blustery Hugo Weaving). It is a process that lures an entire town into a grisly Faustian bargain.