Its scatological humour has won plaudits among a teenage demographic, while older viewers revel in its nostalgic take on their school days, a time when awkwardness around the opposite sex was as commonplace as outbreaks of acne.
Now, The Inbetweeners, the television series that follows four friends at the fictional Rudge Park Comprehensive, is transferring to the big screen. When The Inbetweeners Movie opens nationwide next Wednesday, the show's writers will run a gauntlet that many comedic brands have faced: Ali G, Kevin and Perry and Mr Bean tried to make the leap from TV to film and in doing so fell into the jaws of hungry critics. However, the makers of The Inbetweeners Movie are confident that their characters' swansong has enough of an emotional punch to sustain interest for 90 minutes.
"It's got so much more of an emotional heart than the television series does," says Simon Bird, 26, who plays the know-it-all posh sixth-former Will. "The priority for a 23-minute sitcom has to be the jokes. The writers, Iain [Morris] and Damon [Beesley] had been sharp enough to realise that wouldn't work for a film. They needed something extra."
The "something extra" is a sense of "coming of age" for the teenagers – Will, Simon (Joe Thomas), Jay (James Buckley) and Neil (Blake Harrison) – who at the end of the film are expected to go their separate ways. That will not come without disappointment for fans and cast, as those involved say working on the show has been a familial experience.
Morris and Beesley met when they both worked as producers on Channel 4's The 11 O'Clock Show. The first series of The Inbetweeners aired on E4 in May 2008 and then transferred to Channel 4 the following year. Ben Palmer, who has worked with Russell Brand and Leigh Francis, directed the film. He has been involved since the second series, in 2009.
"From what I've heard from other people working in TV, this very close experience doesn't come around very often," says Bird. "There was a real family feel. Iain and Damon had total control from the beginning – they created it via their own production company. Filming it was full of pranks and a lot of fun and it didn't feel like a job in any way. I would love to work with them again."
The show has often been praised for its catch-all characterisation, which isn't subtle but which has thrust it into the mainstream. Will is high-minded but lacks common sense; Simon is romantic but hopeless at romance; Jay is a loudmouth and Neil is unintelligent but possesses sexual prowess that the others lack. Such clichés help to explain the TV show's appeal, which rests on teenage, regressive humour – jokes about sex and masturbation and frequent swearing make audiences laugh despite themselves.
Morris says he was drawn to teenagers because the demographic was well-covered in the US – shows like NBC's Freaks and Geeks capitalised on the humour that surrounds disjointed, sexually disenfranchised adolescence – but had not been tackled properly in Britain.
Conveniently, swearing teenagers provide an excuse for writers to plumb the depths: it is easier to laugh at teenagers making politically incorrect comments – eg: insulting each others' mothers, delivering borderline homophobic and sexist remarks that most left-leaning newspaper journalists spend their careers condemning – than to laugh at such things voiced by an adult, who should know better.
"I think there's a sense in which being a teenager means you say what you think might shock people," says Morris. "You want to see how far you can push things, and that is part of finding your own personality. You get a lot of leeway from your parents and society. That kind of freedom leads to terrible situations. You haven't got the benefit of experience. The other thing is that you think you know what you're doing, and that's fertile ground for comedy."
Bird, a president of Cambridge Footlights, is well suited to playing a geeky character. At 26 he can pass for someone 10 years younger, and he comes from the David Mitchell school of comedy, in which a performer, while being marginally more cool in real life than the character they make their name playing, enjoys success based on the similarity between them.
"I think I'm not as pretentious as Will is," Bird says. "And I hope I'm not as misguided. Will is the cleverest, but it is book smarts. He has no tact or ability to forsee how some of Jay and Neil's plans might go awry. So I hope I have common sense than all of that."
The film's high jinks have not eroded its right-thinking core. The Inbetweeners Movie stars the disabled actress Storme Toolis, playing a disabled role. This is relevant because of recent stories in the press about the director of the American series Glee, for example, favouring able-bodied actors in such roles because of what is claimed to be a lack of qualified professionals who are disabled.
"It strikes me as the new blacking up – let's call it 'cripping up'," wrote Toolis's mother, the children's rights campaigner Dea Birkett, in The Daily Telegraph this week. "From Tom Cruise in Born on the Fourth of July to the wheelchair dancer in Glee, non-disabled actors have grabbed all the good wheel-on parts."
"Storme did a brilliant job in the film," says Bird. "It would be odd to get an able-bodied actress to play that part when she could do it so well herself."
So what next? Apart from a trip to the Edinburgh Fringe to see many of his friends perform, Bird has completed a pilot called Chickens, which will be shown on Channel 4 next month.
"It's about three men who don't go off to battle during the First World War," says the actor. "It's a show that I've been working on with Joe [fellow Inbetweeners star Thomas] for years and we have been cast together. The women in the village all hate the three main protagonists, because they think they are cowards."
'The Inbetweeners Movie' opens nationwide on Wednesday