If we could tap the goodwill of the audience going into The Muppets, we could probably power the country for a year. Factor into that the goodwill shown by the filmmakers towards Jim Henson's puppet creations, and we could probably do the same for a decade. James Bobin's film is less a continuation of the Muppet movies of yore than the most affectionate of homages to them, and what they represented: it's fan fiction, essentially, penned by New American Comedians, for whom sincerity is not a lost art, and sponsored by Disney. The script (by the human lead, Jason Segel, and his Forgetting Sarah Marshall cohort Nicholas Stoller) and the songs (for yes, there are songs, orchestrated by Bret McKenzie, of Flight of the Conchords fame) establish an alternative universe wherein puppets watch The Muppet Show at home with their human siblings, kids are disappointed when they break up from school (dare I say you would be too, if you had Amy Adams for a teacher?), and everybody breaks into mass dance routines at regular intervals.
The narrative, for its part, is a very meta take on the oldest plot in the showbiz book. While visiting Los Angeles with his brother Gary (Segel) and Gary's fiancee Mary (Adams) puppet Muppet nut Walter is so distressed at the disrepair the old Muppet Studios have fallen into that he sets out to urge Kermit, now living in seclusion in the Hollywood Hills, to get the old gang back together, and light the lights once more. So here they are again, a few rungs lower on the showbusiness ladder than when we last encountered them: Fozzie, his eyebrows a shade greyer, now fronting a tribute act ("The Moopets") stuck with a makeshift human Animal substitute on drums; Gonzo, now enjoying (or is it reduced to?) the status of a home-plumbing magnate, even as he continues to hold onto his old Great Gonzo cape beneath his suit; Animal himself, now attending anger management classes alongside Jack Black; and, last but never least, Miss Piggy, who - as Mademoiselle Cochonnée - has made a new name for herself as plus-size editor of Paris Vogue.
Of course, it's always possible these names no longer mean a thing to a generation who greet the annual arrival to the festive broadcast schedules of The Muppet Christmas Carol, and the reverence in which viewers of a certain age hold it, with a shrug and a "whatever". That would be a pity, because at its peak, The Muppet Show was a guarantor of subversive, anarchic, crucially funny teatime entertainment for all ages. With The Simpsons heading into an agreeably cosy dotage, Harry Hill's TV Burp is probably the closest thing we have to it these days; in all these cases, you sense these shows could get away with anything, such is their resemblance to innocuous children's television. The anything-goes format, in the Muppets' case, was such that celebrities - and comedians, in particular - were falling over themselves to come aboard; the new film duly has an over-the-little-ones'-heads nod to the days of "Julie Andrews and Dom DeLuise cameos".
As in Betty Thomas's similarly meta The Brady Bunch Movie (a tougher sell to foreign markets), the characters' obsolescence provides 50% of the gags. Once reunited, the Muppets are initially rejected by a TV exec (Rashida Jones) who deems their schtick as as old and threadbare as Fozzie's boater in the age of such (fictional, but not entirely incredible) family entertainments as the Ken Jeong-hosted Punch Teacher. In these early stages, Bobin, Segel and Stoller seem to be making a conscious attempt to undercut the joke, as though, while They Can't Believe They're Making a Muppet Movie, they still can't quite believe they're making a movie with Muppets in it. When Kermit first appears, it's to the sound of celestial music that turns out to be a choir in a passing minibus; his halo is revealed as the minibus's headlights.
Overall, though, one has to say the filmmakers protest too much: the turns represented by each Muppet hold up just fine, and the fanboys at the helm dot these well-honed routines with fresh, welcome notes. Segel and Stoller do something slyly clever in ushering centre-stage the newbie Walter, an outsider in both Muppet and human terms, whose inchoate personality will presumably provide an identification point for those younger viewers who've no idea who Beaker is, and may - like Walter - feel overwhelmed by the bustling, chaotic world around them. Given this new recruit's destiny - to become part of the Muppet ensemble - it's actually no real surprise the film should have been denounced by Fox News for spreading collectivist, even Communist propaganda. There's also a streak of gonzo (Gonzo?) logic in how sniping critics Statler and Waldorf have come to throw their allegiances in with Tex Richman (Chris Cooper), the industrialist bent on tapping the Muppets' lot for oil.
In truth, the film lags a little for inspiration in its final half-hour, which really is just Bobin having a shot at his boyhood dream of directing an episode of The Muppet Show: if I were to offer any Statlerish notes from my position in the gods, I'd say this one could do without Kermit's soppy balladeering - the drippy platitudes of "The Rainbow Connection" always did seem to me to belong more to Henson's far cuddlier work on Sesame Street - and with another big celeb cameo for additional oomph. (After Gulliver's Travels and The Big Year, I'm guessing Jack Black comes pretty cheap.)
Still, enough enthusiasm is conveyed, both before and behind the camera, to get the thing over the line, and - besides - you wouldn't want to lose the cover version of "Smells Like Teen Spirit" that finds an unexpected fix to the problem of couching the word "libido" within the context of a PG-rated Disney entertainment. In the end, The Muppets works because it's been assembled by filmmakers and performers who realise jokes can reveal truths about character, that songs can push a narrative along as well as dialogue, and that puppets, like the human tagalongs in this world (and Segel and Adams are tremendous sports), have feelings, too. Get there early, as it's preceded by another of Pixar's superlative short films, picking up where the finale of Toy Story 3 left off. The whole isn't quite the pop-cultural gamechanger advance buzz may have lead us to believe, but as a value-for-money package for young and old this half-term, it's very hard to beat.
The Muppets opens in cinemas nationwide from Friday.