"I am being very insulting about my home town," agrees Lancashire-born Steve Coogan happily, when charged with poking fun at Manchester in his new 'documentary' Alan Partridge's Scissored Isle. "It exercises my Northern chippiness, and has Alan mobilise and articulate that patronising attitude towards the north."

The one-off show sees Coogan's most famous fictional character, fumbling Norwich radio presenter Alan Partridge, lose his cool spectacularly live on air, yelling "chav" at a guest.

As an apology, Coogan - who lives in Ovingdean - decides to go on a journey around the UK meeting 'real people', and get to grips with his own bigotry.

Of course, nothing quite goes to plan.

"It was really fun to allow Alan to have his take on the documentary format," explains writer Rob Gibbons. "It felt quite timely - it contains that element of public shaming, which I know [journalist] Jon Ronson is making some money out of now."

"There's self-shame as well," joins in fellow writer, Neil Gibbons (he and Rob are twins). "There's a trend for people to really self-flagellate because they think it shows humility, so Alan's take on this was, rather than not mentioning what he'd done, he would gain points for it."

"In being prejudiced, he saw an opportunity to spin it in his favour," sums up Coogan, 50, with a laugh.

"Even naturally xenophobic Middle-Englanders realise there are certain views you have to keep under a bushel these days, and you have to present things in a more liberal-friendly way," he adds. "The thing at the moment, even for people on the right, is to be economically conservative but socially liberal, and Alan's cottoned on to that."

During the hour long mockumentary, Alan tours the north, works behind the checkout at Tesco - he's a natural at it - hangs out with a 'gang' of youths (while wearing a stab vest), and goes foraging with a freegan (played by Karl Theobald).

It could easily slip into being cruel and judgemental, but Coogan is adamant: "We're very careful about this. We won't do that bullying comedy, which is picking on people who are genuinely weak and dispossessed, or in some way genuine victims. We avoid that hectoring, bulling comedy. We leave that to the old presenters of Top Gear.

"We always make sure that if we pick on someone like that, the joke is quite clearly on Alan and his prejudice."

Coogan, whose career began on Spitting Image back in the early-Eighties, has now been working with Neil and Rob on Partridge storylines for several years.

After his earlier collaborators were poached and Alan had been shelved for some time, he decided to ask them to come up with some material ad hoc, and everything just clicked.

"I remember reading it going, 'This is fantastic, this is really funny, they get it!' A lot of people think they understand the character, they don't - it was so spot on, I remember reading it and laughing out loud, thinking, 'Eureka!'

"I also realised there was a different flavour to it. As soon as I saw that, I thought the film [2013's Alan Partridge: Alpha Papa] and other incarnations of Alan were possible.

"They've brought real pathos and humanity to him that he didn't have early on," Coogan adds. "If you look at some of the early stuff, although it's funny, it's very much schadenfreude - looking at the fool making mistakes and getting things wrong.

"The tone of the material has become more sophisticated."

"Well, we really saw what you're capable of in terms of your range when you did Around The World In 80 Days with Jackie Chan..." quips Rob.

The Scissored Isle was, says Coogan, a chance to develop the character even further, and a confessional documentary seemed the ideal fit.

For true Partridge fans, it is even a Peartree Productions film - so you have Alan being filmed, talking to camera as the producer and maker of the documentary, and then also the bits most people would cut out.

"Alan has such a lax attitude to quality control," says Neil, "and he'd probably have p**sed the editor off, so the editor would quite reasonably have left them in to shaft him."

"And he may have left some of those things in because he thinks it 'keeps it real'," adds Coogan rather affectionately.

It's this affection Alan Partridge manages to elicit, for his social awkwardness and willingness to keep on going, that makes the character so enduring.

"There's something we find funny about someone struggling with the social mores surrounding a more tolerant society, and seeing someone trying to say the right thing, rather than someone who's just secretly racist or homophobic," says Coogan. "There's a sincerity to it and a ham-fistedness - it's the kind of thing you see among the older generation, who are trying to keep up with social change.

"David Cameron is a very strong role model, because there's that sort of blokishness he tries to pull off, and an approachability - that's what Alan aspires to."

Coogan and the Gibbons also create mockumentary sitcom Mid Morning Matters together, which focuses on the minutiae of Alan's show on fictional radio station, North Norfolk Digital.

"The die-hard fans love Mid Morning Matters because it's pure, and all about character detail, because you're boxed in - literally - in the radio studio," explains Coogan. "It's all planned with great precision, every look to the camera and aside, a moment of insecurity, an interjection from Tim Key [Sidekick Simon]. Ostensibly, the episodes look quite straightforward, but in the execution, it's complex."

They're also working on Alan's next book, Alan Partridge: Nomad, due out later this year, in which the faux broadcaster mimics the trend for stories where a famous name retraces a momentous journey made by their forefathers, the only problem being that Alan's ancestors haven't made any momentous journeys.

"He doesn't actually leave Britain!"

A second film is also potentially in the offing, while Coogan also admits, "I quite fancy doing a chat show."

And who wouldn't want to watch Partridge do that?

:: Alan Partridge's Scissored Isle airs on Sky Atlantic on Monday, May 30