Mike Nichols and Elaine May, in one of their old comedy routines, could have skewered the dialogue in The Heart of Me. Man to his wife's sister before the two commence an affair: ''It's raining.'' Woman: ''Yes, I shall get wet.'' Mother of the sisters to her son-in-law after engineering an end to the liaison: ''I think I should prefer if we did not discuss this any further.'' Rah-ther!
Yet in their own precisely posed ways, the drenched players in ''The Heart of Me'' are as compelling as those in any less decorum-bound love triangle. And director Thaddeus O'Sullivan's handsome production, based on Rosamond Lehmann's 1953 novel ''The Echoing Grove'' (adapted into a genteel script by Lucinda Coxon), is a satisfying piece of BBC Kabuki set in London before, during, and after World War II. Besides, the actors demonstrate such unmatchable Englishness that the movie -- a kind of ''End of the Affair'' without the religious instruction -- takes on the gleam of a cultural artifact. ''The Sixth Sense'''s Olivia Williams goes for cold graciousness as the wife; Helena Bonham Carter smolders and storms -- her specialty, characteristically emphasized by smudged eye shadow -- as the untamable sister. Playing the man in the middle, ''A Beautiful Mind'''s Paul Bettany again demonstrates his skill at suggesting a hot core beneath his freckled paleness. And for a genre bonus, veteran Eleanor Bron (''Help!'') has a fine, eyebrow-arching time as the meddling mother-in-law.