The Knight of the Burning Pestle, Sam Wanamaker Playhouse

If it's possible to have rather too much of a frolicsome thing, consider by way of example The Knight of the Burning Pestle, a giddily self-conscious 1607 romp from Francis Beaumont that would be more fun if it were at least a full scene or two shorter.

The problem lies not in the space but in a species of entertainment that by its very nature wears thin: there's a reason why sketch comedy is called what it is and why few epic plays or films tend towards hilarity. The invention needed to send a piece like this soaring is difficult to sustain across three hours or more. 

That's not to say that the director, Adele Thomas, lacks imagination and spark, and she is abetted by a fight director in Kevin McCurdy who offers up some of the most convincing head-banging (and more) that I've ever seen in a theatre. But as we watch a growly grocer (Phil Daniels's Citizen) and his none-too-demure spouse (Pauline McLynn as Wife, pictured below right) derail a planned entertainment so that they can give pride of place to their beloved apprentice, Rafe (Matthew Needham), it's hard not to feel one's ready grin tipping into the territory of grin-and-bear it, no matter how consistently wonderful McLynn, in particular, proves to be.   

Indeed, one could feast on McLynn's comic timing all evening, as she rises from her seat down front in the stalls to stalk the auditorium, shouting encouragement at Needham's sweetly earnest Rafe and chattering and chomping her way through many a scene as if on some sort of post-Elizabethan outing to Dirty Dancing. (Daniels, pictured below left, by contrast, is comparatively wasted.) Having put paid to The London Merchant, the show that was supposed to be on offer, this ever-restless playgoer - we all know the type! - risks becoming her own show, and McLynn summons at once the sort of unruly spectator whom you don't have to roam far and wide to find in London theatres these days. 

As it happens, her misrule is more engaging over time than the picaresque play-within-a-play, which from our modern-day perspective suggests a peculiar amalgam of Don Quixote and Into the Woods, as those disparate works might look put through a Monty Python-style blender. (One keeps expecting the knights who say "Ni!" to stop by for a spell.) There's much made of slaying a giant and of making one's way to exotic locales like Mile End, while no corpse is too inert not to rise again, as might be expected from a purposely life-giving narrative containing a family that goes by the cheerful compound, Merrythought. 

In keeping with the spirit of comedy, mirth is seen to prevail (Paul Rider's hyper-exuberant Merrythought pere voices a paean to precisely that) via multiple couplings that allow love to have its day and Rafe to suggest some kind of embryonically banner-waving if inevitably more bumptious Henry V. It's good to see Malfi alumnus Alex Waldmann - here cast as an avid suitor called Jasper (rhymes, we're helpfully informed, with "clasper") - cutting loose to a degree unusual for him, and Dickon Tyrrell's Humphrey finds the panache in pomposity, intoning "walk around me" to anyone stupid enough to get in his way. Both actors on this evidence would be great in One Man, Two Guvnors, if that exercise in comic delirium weren't on the verge of leaving town. 

The audience, too, gets into the act, at least those near enough to the action to be offered a drink or to find one actor or another tumbling into their lap, and with three four-minute "interludes" plus a proper interval, today's diminished attention span is certainly catered for by having a meandering play served up in sitcom-style chunks. But if you want to have a really good time, pay less heed to such rhymes as "bellies" with "shellies" (the latter as in what snails have) and more to McLynn's pinched visage in fevered pursuit of aesthetic satisfaction. In fact, a thought occurred to me midway through: now that Dame Edna is retiring, maybe McLynn's take-no-prisoners Wife might consider taking the Ozzie mega-star's place?

• The Knight of the Burning Pestle is at the Sam Wanamaker Playhouse until 30 March