I have to confess to being something of a Monty Python agnostic, having never found their brand of bloke-ish, deliberately daft but somewhat smugly knowing Oxbridge humour hugely to my taste. Luckily, Eric Idle and John Du Prez’s much-lauded musical is more than simply a fan-pleasing reheated mega-mix of best bits — and the addition to the London cast of Simon Russell Beale, whose bumbling, pop-eyed King Arthur previously graced the Broadway production, should have audiences doing a fish-slapping dance of delight.

The show, as even a dead parrot could probably tell you, is “lovingly ripped off” from the film Monty Python and the Holy Grail, but Idle cleverly combines the legendary quest of the Knights of the Round Table with an all-singing, all-dancing account of their attempts — at the capricious insistence of bearded, squeaking Knights of Ni — to mount a West End musical.

This allows for much adroit sending-up of musical theatre itself, with parodies of everything from Sondheim’s Company to Andrew Lloyd Webber’s Phantom of the Opera, Fiddler on the Roof and — deliciously, given how long the Palace stage was home to its revolutionary Tricolore-waving and barricade-mounting — Les Misérables. It’s all executed, in Mike Nichols’s rollicking production, sharply choreographed by Casey Nicholaw and designed in the manner of Terry Gilliam’s iconic animations by Tim Hatley, with such slick wit, and such a big-hearted sense of fun, that it’s impossible not to succumb.

As for Russell Beale, he’s a buffoon you long to cuddle. Trotting majestically about on an invisible steed to the sound of clacking coconut shells, shuddering at the effrontery of a clique of filthy-mouthed, flatulent Frenchmen (led by an exuberant Tom Goodman-Hill) or facing down a fanged killer rabbit, he exudes pomposity and wounded dignity, while conveying, in numerous little moues and asides, the incompetence and nagging sense of self-doubt that make him loveable.

He’s the clowning glory of a cast bursting with comic brio, in which Hannah Waddingham’s Lady of the Lake diva still stands out like a figurehead of foolery, wrapping her gob-smacking voice around the score’s showtune pastiche. Spamalot hasn’t quite made a Python convert of me, and for all its panache it’s distinctly disposable. But it’s a jolly, joyous extravaganza of extreme silliness.

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