With The Inbetweeners Movie proving to be a giant unexpected box office hit of 2011, it was only a matter of time before another UK comedy TV creation was granted the big screen treatment. Luckily this time round the creation is much more loved, much more interesting, and most importantly, a whole lot funnier. Enter the unsinkable comic behemoth that is Alan Partridge whose social ineptitudes, insecurities and delusions have somehow remained as inescapably funny as they were over a decade ago.

The risk of Alan Partridge: Alpha Papa is if it were to, as so many other TV comedy to film spin-offs have done in the past, aim too big. Usually this takes the form of sending a show's characters out of their usual world, typically by sending them abroad, and typically this method fails. The writers of Alpha Papa however (Armando Iannucci, Steve Coogan, Rob and Neil Gibbons and Peter Baynham) are cannier than this. Instead they shrewdly keep Alan at home, left in the familiar world of Norfolk, aka 'The Wales of the East', to continue his life as a Radio DJ developed recently in the excellent Mid Morning Matters web series.

As Alan starts his day discussing with the loyal listeners of North Norfolk Digital who the worst 'monger' is (fish, iron, war?), one joyfully realises that nothing much has changed for our favourite middle aged Bond and Toblerone enthusiast. But the world around him is changing for his beloved radio station is being taken over by slimy corporate bullies Gordale Media who favour the moronic younger DJs of Radio 1 to Alan and ageing DJ Pat's gentler shows. But when the Gordale Media heads (who want to re-brand the station as Shape) decide to "just sack Pat" following Alan's confidential and naturally self preserving advice, the disillusioned Irishman unexpectedly returns for the office party with a shotgun to take everyone hostage. Cue the Alpha Papa who, after a hilariously brief car ride to the local police statio, is sent into the siege as Pat's trusted communicator. While the scenario set up is necessarily suited for the bigger screen, it's kept to its simplest form to let a never ending stream of jokes run through.

If anything, the context of a film incarnation has put a rewarding pressure onto the writers. Suffice to say, Alpha Papa's gag rate is extraordinary. Not only is the quantity dizzyingly high but the quality matches too. There's a supposed whole other feature length film of material cut from Alpha Papa that makes the jokes that survived the cutting floor really choice cuts. But what could have turned out just as an extended episode is actually a very decent film in its own right. The standard cinematic narrative arcs are present with even a small love interest thrown in for good measure. The actors, primarily all from the small screen, also hold up very well. The best of the bunch, asides from Coogan's comic tour de force performance, is Colm Meaney who portrays the broken Pat with a touching sense of despair and heartbreak. He sidesteps the archetypal crazy gunman caricature for this more sincerely broken vision that lends an unanticipated emotional weight to the film.

The star here undoubtedly is Coogan, minus the ageing makeup, who one forgets is buried deep underneath the mask of his comedic alter ego. Partridge is Coogan's Mr Hyde, bubbling to surface every now and then to haunt the actor. Alpha Papa therefore is an act of exorcism of this Lynx and Lexus (sorry Lexi) loving demon. But it's not a damning kick in the mud for the character, more a big tasty treat for him to enjoy. For Alan is of course the hero of his own action film essentially, as if he were behind the camera himself. The real man behind the camera is actually Declan Lowney, director of the first two series of Father Ted, who pulls off the delicate task of crossing the tiny and personal world of Partridge into the grander realm of cinema with impressive ease. But while Alan maybe behind the camera (well maybe more behind the overall concept of the film shall we say), thankfully he's not immune to the writer's customary ill treatment.

Don't mistake Alpha Papa as a Die Hard vehicle for Alan; it's just as a painfully embarrassing day in the life for him as we're used to gleefully watching. John McClane for one wouldn't have got his trousers and underwear snagged off his body while trying to climb through a window. And when the police ask him to put his hands in the air, he certainly wouldn't have resorted to Alan's method of modesty (in what will surely be by far the most scarring reveal shot of this year).

In fact the most ambitious action scene in the entire film suitably takes place in Alan's daydreams. Even Lynn, Michael and an amusingly more damaged Dave Clifton return to make Alpha Papa as familiar and cosy as fans would want. The finale, set on Cromer pier, riffs rather unsettlingly on the Raoul Moats and Derek Birds of recent memory, but finally makes proper use of the cinematic scope that's restricted in the main office building set. It's this deft balancing act of keeping the faithful DNA of Partridge alongside some bigger screen action staple moments that makes Alpha Papa such a triumph. Overall for a cinematic outing of one of the least cinematic characters of all time, Alpha Papa exceeds expectations considerably. This really is, in the words of Shakin' Stevens, 'lovely stuff'.