THE air of expectancy which Frank McGuinness's new play for the RSC has generated was heightened by a thunderous explosion which accompanied the dimming of the house lights.

Thereafter, his analysis of the Gunpowder Plot contained far more emotional and intellectual fireworks than clever theatrical pyrotechnics. This is, to a great extent, the Gunpowder Plot without the plotters, and it certainly lacks clusters of bearded men in sticky-up hats mumbling in corners. It also puts Guy Fawkes in his place. He appears, briefly, played by a watchful Barry Aird, but his role is as the heartless mechanic, the man who knew about explosives.

McGuinness's interest lies instead in the climate of conspiracy and blind religious hatred which poisoned Britain in the early Jacobean age, and with the personalities of some of its key players.

The motives of the conspirators themselves are dismissed fairly easily - Robert Catesby (Jonjo O'Neill) and Robin Wintour (Matt Ryan) are rich, pretty-boy adventurers, albeit passionate Catholics.

But other souls are body-searched through the use of The Equivocator, played as a teasing, sensual, scouse satyr by Kevin Harvey. His role is to force the characters to question their own motivations, as if Hamlet, in asking 'To be?' was answered by his own reflection with 'Or not to be?'. Thus, for example, James's cruel spymaster Robert Cecil, superbly played by Nigel Cooke, is revealed as a man full of doubt, and James's queen Anne (Teresa Banham) acknowledges her secret Catholicism.

The other fascinating study is of James himself, an erratic, sexually ambiguous fop, played to perfection by William Houston, who has illuminated the Swan this season with three unforgettable performances, notably as Sejanus.

Speaking Like Magpies is no sort of history lesson but it has a Freudian fascination and several grand theatrical moments.

Speaking Like Magpies runs in repertory until November 5.

Review by STEVE EVANS