Threatre: One nation under a groove

Up Against the Wall

Tricycle, London

The Prisoner of Second Avenue

Haymarket, London

Sacred Heart

Royal Court Upstairs, London

T he "Seventies musical" is a fail-safe concept. Roll out the hits, intersperse them with a semblance of plot, and, hey disco!, the audience is wriggling and whooping in its seats and whistling all the way home. It's less cathartic than a boogie at a retro club, but you don't have to suffer the sweat and blisters.

In the Black Theatre Co-Operative's , this easy indulgence is subverted. It's a musical about putting on a compilation musical called ... "". The Blaxploitation-era songs need a "connecting thread", but the placid thirty- something writer from Surrey (Noel McKoy) can't think of one. Then a cast member demands: "What's it all about? A bunch of songs from way back when, or a bunch of songs from way back when it was exactly like it is now?" Or, "when you're up against the wall" are you singing "Shaft", wearing afros and leopard-prints, and pretending to be superfly hustlers? Or are you having a chance meeting with a "pig" in Brixton?

Felix Cross and Paulette Randall's self-referential script tries to have it both ways. It parodies Seventies stereotypes, but creates Nineties ciphers: a convent-schooled innocent (wide-eyed Lorna Brown); a self- centred diva in decline (sassy Suzanne Packer); a politicised young dope- smoker (the compelling Mark McLean, whose stinging Black Panther audition piece opens the Tricycle show); and a lecherous alcoholic director (Clinton Blake). As the show's deus ex machina, it is Blake who provides the "connecting thread", then leads his disparate soul-mates in "One Nation Under a Groove".

Despite such contrivances, this is, well, a fantastic compilation musical. The first-half "rehearsal" has belting showcases and corny choreography from the uniformly excellent performers, backed by a funky four-piece band. The second-half "performance" has more of the same, this time with costumes. Such showmanship does make any use of song-as-narrative seem false, but there's a notable exception. An elegiac rap poem on Brixton street life, superbly delivered by McLean, drips with political passion - a chance to "tell it like it is". So it's a let-down and a bonus that opts to "dance it like it was", instead.

There's no singing or dancing in Neil Simon's 1971 comedy The Prisoner of Second Avenue, but there is a lot of stale cheesiness. In a sitcom- type apartment, Mel (Richard Dreyfuss) is having a sitcom-type breakdown. Dogs bark, cars honk, neighbours carouse; and there's a heatwave. Mel can't sleep. So he strides about gesticulating and shouting at his wife, Edna (Marsha Mason). Then he bangs on the wall and hollers on the balcony. A few days later, he loses his job (in a mass redundancy), his possessions (in a preventable burglary) and his mind. Well, you would, wouldn't you? Except, this being Simon, you'd be pithy and sardonic during your paranoid delusions; you'd be cute when sedated, and philosophically serene when cured.

Dreyfuss milks the acerbic one-liners and pads out the farce, and his timing is faultless. Mason falls prey to overactive hand-acting in a role that only demands ditziness: Edna is a wife who leaves the door open in, we're reminded, the city with the world's highest crime rate.

Simon has complacently stated that the play could have been "written about the New York of 1999". But aside from work pressure - hey, did employees eat lunch at their desks then, too? - and city stresses, it won't enlighten anyone with even the most tenuous hold on their own life. And a patronising sexism runs through it, underpinning the dynamics of the central relationship and manifesting itself in the inane chorusing and kow-towing of Mel's three sisters towards his big-shot brother.

In Mick Mahoney's Sacred Heart, the last in a collaborative season between the Royal Court and the National Theatre Studio, three friends are reunited with a fourth, last seen 18 years before. Pat and Kate are a London-Irish couple with teenage children; Line is a black single mother; Jerry, the returnee, is a divorced millionaire property developer. He's suave, charismatic and cagey (he is Michael French, the excellent ex-EastEnders charmer after all); he also used to be Pat's best mate. The foursome reminisce, accuse and confess as they pace around their former Friday-night stomping ground, a church social hall. And Francis O'Connor's design makes industrious use of the space at the back of the Ambassador's.

Big issues arise - bigotry, class, money, parenthood, football - and are left hanging. It's the meaning and responsibility of relationships that Mahoney picks at: the unspoken jealousies and unfulfilled promises which friendship obscures; and the callous courage necessary for it to be betrayed. Mahoney's script is caustic and relentlessly staccato (nobody gets past a couple of lines without an interjection). Edward Hall's direction keeps the movement as circuitous as the exchanges over an unbroken 90 minutes, and the volleys are well handled by the cast. Doon Mackichan is an unaffected, complex Kate; Ewan Stewart seethes and simmers as Pat, the honourable builder. Like all the best arguments, Sacred Heart is about everything and nothing. And its logic and motivation are just as unpredictable.

`': Tricycle, NW6 (0171 328 1000), to 17 April. `The Prisoner of Second Avenue': Theatre Royal, SW1 (0171 930 8800), to July. `Sacred Heart': Royal Court Upstairs, WC2 (0171 565 5000), to 24 April.

Robert Butler is away.