First performed in 1991, The Madness of George III is one of the most powerful, moving and evocative plays ever written about actual events in the eighteenth century, and was successfully adapted into a popular film in 1994 as The Madness of King George. The cast of this revival of the original play by Alan Bennett is large and filled with familiar faces. The lead and title role of the Kng is expertly and energetically played by David Haig. From the lively, caring monarch at the beginning of the play, an entertaining image of ‘Farmer George’, to the bitter ruler mourning the loss of America in the War of Independence, arguing with his pompous buffoon of a son, or suffering from a dangerous illness, Haig plays this key part with an unstoppable zeal, and leaves the audience wondering at his superhuman energy – and wondering where the time went.

Haig also plays George as if he has researched the role carefully. Modern historians believe that George III was suffering from ‘acute intermittent porphyria’, of which one symptom is mental disturbance due to nerve deterioration. Doctors at the time were baffled by his illness. Haig is careful to play him not simply as a madman, but as somebody who is mad but thinks he is sane, or becomes aware that he is ill but is at a loss to explain what is happening to him. Here the King’s ‘madness’ becomes something complex, at times even endearing, rather than violent or frightening. There is no hard-and-fast line of demarcation between sanity and lunacy, yet the audience is consistently aware of the King’s state of mental health, and the ‘mad’ moments are easily comprehended and even empathized with, especially when the patient is brutally restrained by his doctors.

There is more madness in Karren Winchester’s cameo as Margaret Nicholson, the regicidal ‘madwoman’ who attacks the King, in a shocking interlude to the graceful and ceremonious appearances of the Georgian Court, attempting to end the King’s life with a blunt dessert-knife. George impresses everyone by declining to have her executed, but having her sent to the Bethlehem Royal Hospital instead. By pointed contrast, Bennett’s doctors hardly show the King much in the way of similar kindness during his bouts of madness; instead they fight among themselves for the privilege of curing for him. Sir George Baker, the first physician in line, is well portrayed by Peter Pacey as a distinguished quack. Madhav Sharma makes a debonair Dr Richard Warren. John Webb takes the comedy even further with his turn as Sir Lucas Pepys, who is gleefully obsessed with the contents of the King’s chamberpot.

Clive Francis’s Dr Francis Willis makes a macabre contrast to the other doctors, particularly when he restrains the King in a leather-strapped chair, as George pleads to see his wife. But Francis’s Dr Willis does not strain the quality of mercy once his charge starts to recover and he is freed from his temporary prison of ‘beneficial’ medical intentions. Willis was a clergyman as well as a doctor of medicine, a duality that comes through here in his sometimes ferocious, sometimes tender treatment of a patient who, when quieted, acts as a sorrowful penitent.

Both Christopher Keegan as the Prince of Wales and William Belchambers as the Duke of York made superbly appalling princes, the one easily led by his brother, the other pompous, irritating, childish, and nasty – yet Keegan also gave the Prince a foppish air, bounding about the stage like a colourful and crazy bird. From a theatre historian’s perspective, it is amusing to see these real lives acted out on a modern stage, particularly as, historically, the royal family drama extended to the theatre itself: one evening at the Theatre Royal, Drury Lane, the King and Prince arrived independently, and met under the theatre’s rotunda, whereupon the King promptly boxed his son’s ears. The theatre’s managers created separate entrances, which still exist today, in the hope of avoiding further conflict.

More harmoniously, Beatie Edney makes a wonderful Queen Charlotte, determined to protect her husband, not least from the machinations of her own son. Charlotte Asprey plays Lady Pembroke, the Queen’s lady of the bedchamber, who, as the only other lead female character, makes an obvious contrast with the Queen. When the King in his madness bestows unrequited favours on her, she has to reject his advances with a grace and concern fitting to a lady of ‘quality’, without giving offence. The poise with which Asprey plays the part is perfect.

There are further fine performances from the supporting cast, including Nicholas Rowe as the Prime Minister, William Pitt, Ed Cooper Clarke as the dashing Captain Fitzroy and Orlando James as Captain Greville, as well as George’s devoted footmen and servants, whose concern for him provides a refreshing alternative to the doctors’ awful treatment of him. The action is elegantly set on an uncluttered stage, with a seemingly vast array of reusable scenery that clearly and convincingly switches from one Royal Palace to another. Suspended in mid-air or pushed effortlessly onto the stage by diligent footmen are outlines of panelling and picture-frames, all fashioned from light, natural-coloured wood. The elaborately carved frames, sans paintings, were nonetheless pictures themselves, down to the ‘cross-hatching’ on the panelling as if in an eighteenth-century engraving. There is no distracting backdrop, just an intervening darkness between frames, wainscoting and doors. The interior of the Royal apartments is cleverly presented by three doors standing alone on the stage, one behind the other but each a little to the right in a ‘staggered’ effect, so that the actors could move from one ‘room’ or ‘corridor’ to another.

Malcolm McKee has provided the production with excellent incidental music, and there are coronation pieces by Handel to complement the script’s anecdote about the King and Queen having George Frederick’s own harpsichord in their palace. The lighting is carefully tailored to each scene and each transition, transforming the royal bedchamber in the gentle glow of candlelight into the dingy palace where George is finally confined. The colours of the costumes and props are a mixture of blood-red and mahogany, mixing royal luxury with stark reminders of human mortality and weakness. In all, this immensely successful revival of the stage version is enjoyable for the purist and the curious alike.

‘The Madness of George III’ by Alan Bennett runs until 31st March 2012 at the Apollo Theatre, London. A Peter Hall Company production; directed by Christopher Luscombe.