Note: The following review dates from April 2002 and the production's initial run at the Donmar Warehouse.

If David Mamet long ago cornered the American playwriting market in transcribing the inarticulate rhythms of everyday verbal interactions into vivid theatrical dialogue, he now has an heir apparent.

Kenneth Lonergan, already represented in London by his raw and revealing first play This Is Our Youth at the West End's Garrick Theatre, now has a more mature, if ultimately less bracing, later work being presented as part of the Donmar Warehouse's American Imports season.

Lonergan's is an original and frequently surprising voice, with a real gift for characterisation if not yet situation. But if the plots of neither play are exactly taxing, they're both efficient and sufficient to provide a context within which to meet his vividly realised characters.

Lobby Hero - set in the lobby of a Manhattan apartment building (clinically rendered in Robert Jones' design) - observes the unnaturally limited night-time traffic there. No wonder Jeff, the lonely 27-year-old doorman of the building (or security officer, as he prefers to be known) contrives to sleep on the job. But tonight the dramas of other people's lives intrude, and he's forced to wake up in more ways than one.

His supervisor is William, whose brother has just been arrested on a murder charge and who tells Jeff that he's considering providing a false alibi for his kin.

The local cops on the beat drop by, too: a rookie policewoman, Dawn, and her more experienced partner, Bill, whom she idolises. While Dawn passes the time in the lobby with Jeff - who in turn confesses his passion for her - Bill goes upstairs to visit one of the female residents on other business.

To say more would be to give away the motor of Lonergan's drama, but the play is actually driven by the revelation of character rather than of plot. As such, it offers four terrific acting roles, each of them inhabited with deftly naturalistic authority by David Tennant (Jeff), Gary McDonald (William), Charlotte Randle (Dawn) and Dominic Rowan (Bill).

Personally, I found myself more wrapped up in the quirky unpredictability of Lonergan's characters in his earlier play; but this time around, he provides far meatier moral issues to debate. As skilfully orchestrated by Mark Brokaw - who also directed this play's Off-Broadway premiere last year - it provides a compelling evening's theatre.

- Mark Shenton