I, Malvolio, Pavilion Theatre, Brighton

A man stands in a horned headdress and sagging, stained undergarments. His shoulders droop, his limbs hang as if dragged downwards by invisible weights and his face is clouded with defeat. "I am not mad," he murmurs, and sets about making the case for his defence.

This is Tim Crouch's take on Twelfth Night, as seen through the eyes of Shakespeare's supercilious steward who is tricked into donning a pair of canary-yellow stockings and grinning inanely at his mistress Olivia until, deemed insane, he is locked in a grubby cell. Malvolio is neither a villain nor a tragic hero yet he is one of the Bard's more memorable figures, a dour, self-regarding, deluded prig who, amid the jollity and resolution of the play's final scenes, resolves that he'll be "revenged on the whole pack of you".

Here we find him fresh from his cell and contemplating suicide. But he is not so defeated that he won't have a pop at the audience for their la-di-dah, beret-wearing, theatre-going ways, or indeed at others who drop litter, chew gum, spit in public, don't go to church, drink too much, talk too loudly or – the greatest sin of all – arrive late for a show. "That kind of arrogance," he rumbles as the latecomers take their seats, "has led this country to where it is today."

Crouch's Malvolio is deliberately loathsome. His long johns are stained around the crotch, flies buzz around his head and his face is smeared in, well, you don't want to know. Deluded he might be, but he is prepared to admit some flaws. In making himself so pitiable, Crouch makes us complicit in his humiliation. The more we laugh, the more he feels vindicated in his view of a world inhabited by boorish, ill-educated bullies who delight in the misery of others.

There's plenty of fun to be had here though the show lacks the pathos of a man whose loneliness and desire to be loved is at the very core of his character. Instead Crouch plays it for laughs. There are repeated refrains and a rather tiresome sight gag involving leopard-print underpants. The lights never go down on an audience whom he frequently draws out of their seats and into the drama.

Malvolio's suffering is evident though it's not enough for us to feel his pain. Entertaining as it is, Crouch's show never recaptures the sadness of that initial figure, sad-eyed and broken, making his plea for sanity.