Downstairs at the Royal Court there's Tarell Alvin McCraney's Wig Out!, an exuberant celebration of the gay world as it's exemplified by Harlem's drag houses but one that barely acknowledges the pain behind the exotic lives on show. Well, in the attic that the Court calls the Theatre Upstairs there's acknowledgement in abundance. How could it be otherwise when Alexi Kaye Campbell's impressive debut gives us three actors embodying three lives as they might have been lived in two very different periods: grey, repressive 1958 and a 2008 that brings its own pressures and difficulties?

This interweaving of eras and comparison of sex lives isn't original. Back in 1979 Caryl Churchill's Cloud Nine switched from Victorian to modern times to make some trenchant points about the complexities of gender. But Campbell's focus is more on changing attitudes to homosexuality. Philip One is a married man who can't admit his feelings and, after an affair with Oliver One, undergoes aversion therapy likely to be as ineffective as it is humiliating. Philip Two is unmarried, as is the far happier woman who was his wife in the earlier incarnation. He sets up house with Oliver Two, but can't stand his lover's promiscuity.

The play is too wordy and sometimes the words sound more artificial than period angst demands, but it makes its point, which is that anything is better than hypocrisy, evasion, denial and lies. I didn't count the number of times “honesty” is mentioned, but on each of many occasions it has an impact. J.J. Feild's prim but dishonest Philip One more or less destroys three people: Bertie Carvel's gentle, rather weak Oliver One, whom he ends up attacking and then raping; Lyndsey Marshal as a wife who eventually twigs the reasons for her deep unease; and, not least, himself.

One of the play's strengths is to do justice to the wife's sense of loss, another to admit that sexual liberation doesn't mean the end of tension and trouble. However, that admission goes only so far. I can't reveal the ending, which occurs on Gay Pride Day and, along with Campbell's invocations of truth and self-respect, gives the play its title. But it's a mite sentimental: 1958 may have been hell; 2008 is still pretty purgatorial.

Box office: 020-7565 5000, to Dec 12

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