Half the stress of a wedding is finalising the guest list. Not so for Confetti director Debbie Isitt, who merely cherry-picks from Brit-com’s current wealth of talent to ensure her nuptials-based mock-doc has the cast it needs to have the audience rolling in the aisles. Name your favourite comedy programme (Green Wing, Spaced, Peep Show, The Office) and you’ll find one of its stars padding out the congregation. Not that Isitt overlooks more seasoned laugh-getters, though, with Mike Leigh stalwarts Alison Steadman and Ron Cook supplying a pair of trademark chippy caricatures.

For her template, however, the Nasty Neighbours writer/ director has a different guest in mind. Christopher Guest to be precise, whose This Is Spinal Tap and Best In Show wrote the playbook on this kind of improvised farce-verité. As in the latter film, an outlandish competition – in this case, a magazine-sponsored contest to find the tackiest themed wedding – provides the dramatic motor. Three deluded couples – two naturists (Robert Webb and Olivia Colman), a musical-loving duo (Martin Freeman and Jessica Stevenson) and a pair of ambitious pro-tennis players (Stephen Mangan and Meredith MacNeill) – each trying to stage a ceremony demented enough to win them a dream home. And, as is customary for this sort of convention-spoofing fare, their trials and tribulations – along with those of the magazine’s opportunistic editors (Felicity Montagu and Jimmy Carr) and their mincingly gay wedding planners (Vincent Franklin and Jason Watkins) – are witnessed by a fly-on-the-wall camera that records every goof, fumble and embarrassed silence for posterity.

Improvised comedy is hardly an exact science, though. Indeed, one of the revelations of this DVD is how much didn’t make it into Isitt’s final cut – a whole hour’s worth of footage, including a hilarious, excruciating encounter with Julia Davis’ sex-obsessed shrink. Throw in no less than three alternate endings and you have a positive surfeit of deleted footage. What’s missing, though, is any insight into Isitt’s working practices and how she shaped her cast’s contributions into a coherent, if far-fetched, whole. Such a behind-the-scenes glimpse might have shown why Mangan and MacNeill’s characters are coarse one-dimensional stereotypes and why the nudist plot strand is so poorly developed compared to the singing’n’dancing rivals’.

Isitt ultimately fails to produce a film on a par with Leigh’s tragi-comic explorations of dysfunctional society, because her protagonists are gormless misfits all too deserving of our derisive titters. As ridiculous as David Brent is, he isn’t entirely devoid of humanity, making us care for him despite his glaring faults. Isitt, though, shows us the warts and nothing else, inviting us to feel smugly superior to her rabble of bumbling losers. The end result certainly tickles the funny bone, but a more sympathetic eye might have plucked the heart strings as well.