George III was not mad. He was almost certainly suffering from a hereditary blood disorder called porphyria that flowed through the veins of many of Europe's royal houses. The title of Alan Bennett's clever drama is clever itself. Who is to say where the madness really lies - with the king, or the clueless doctors and their insane treatments, or the power-mad politicians who tried to manage and manipulate his illness for their own ends? Bennett turns what could be a dull history lesson on the machinations of 18th-century party politics into lively drama that points up the differences between the king as institution and the king as man.
The quack doctors and scheming politicians come in for a walloping, but George himself emerges as a frail human being, a man who - when illness and the doctors' barbaric treatments are not wracking his mind and body - definitely knows what's what. As he himself puts it, when he recovers from the first bout of illness in the late 1780s: "I have remembered how to seem." The monarchy is all about show, the man cloaked and hidden from view by pomp, ceremony and symbolism.
The great thing about Michael Pennington's superb central performance is that he always lets you see the man behind the king. As the doctors - and the heir, the Prince of Wales - do their worst to him, Pennington's sweet-faced king is desperately moving. He is like an 18th-century King Lear, shuffling along on blistered legs, and turning his blind mole-like eyes from the light. This is not just a technically brilliant performance, but one from the heart. It illuminates the stage.
Rachel Kavanaugh's production is hampered by a design of circular steps and wrap-around curtains that create two distinct playing spaces. This magnifies the brevity of Bennett's scenes rather than creating the kind of seamless movement from one to another that was surely intended. It looks stagy, artificial and old-fashioned, rather than cinematic. But the performances are first rate, from the monarch down to the lowliest page.
· Until October 18. Box office: 0113-213 7700. Then transfers to Birmingham Rep.
