When Graham Linehan was a boy growing up in Dublin, he was often bullied: for being a geek and for his size. But, at 6ft 2in, he was also not allowed to fight back. "I was told, 'Never fight. Never, never fight'. I guess my parents were afraid I'd spike someone and they'd fall over and I'd kill them by mistake or something. So they'd tell me: 'Just walk away, walk away'." One day, "a huge group of kids surrounded me and this other guy, and they created this ring, so that I couldn't leave, you know? And I didn't want to join in, so I just waited for my moment and walked out of the ring … "

Decades and much success later – Linehan co-wrote Father Ted and Black Books, writes and directs The IT Crowd for Channel 4, has won four Baftas, and an International Emmy and has contributed, either as writer or director, to many of the seminal comedy shows of the last couple of decades (The Alexei Sayle Show, I'm Alan Partridge, The Day Today, Brass Eye, The Fast Show) – and he's still doing the same thing.

Although now he walks away and it makes the national news. Earlier this week Linehan was asked onto the Today programme to discuss his new stage version of The Ladykillers, which opens at the Liverpool Playhouse (where it has already prompted their fastest first day of ticket sales ever) in early November, and transfers to the West End three weeks later. As he later wrote on his blog, he was told before arriving at the studio that he would be expected to discuss the "problems [of] adapting a classic film for the stage". Arriving in the green room, however, he encountered this paper's drama critic, Michael Billington, who informed him that, in fact, he would be required to defend the wisdom of tampering with such a well-loved classic at all.

Linehan attempted to stay with the detail – the limitations (and advantages) of keeping all the action indoors; the opportunity to explore characters a bit more; the fact that (unlike Some Like It Hot, say) The Ladykillers doesn't have a surfeit of really funny lines, and he wanted to have a go at providing some – but this was treated as him going somewhat off-piste. "Why turn," as Billington put it, "a perfect film into a play?" Linehan refused to be drawn. "You're as bad as a cabinet minister," complained Justin Webb, presenting. But that was exactly Linehan's point. "Michael's been brought on to present the view that there's no point in doing this at all, and I won't get drawn into that kind of a discussion."

But surely – as many promptly pointed out, on blogs and on Twitter – he's a writer; surely he understands the usefulness, the necessity, even, of dramatic conflict? "When you're a writer you learn very quickly that there are ways of writing conflict that are a bit more subtle," says Linehan. "If you're a good writer, you don't have everybody shouting in every scene. Conflict means a mother places something here," – he moves the salt shaker away from the pepper on the table in the sleek west London kitchen he shares with his wife, Helen Serafinowicz, and their two children – "and then when she leaves, the daughter moves it back. That's conflict. It doesn't have to be two people screaming at each other in a room. But the Today programme, and sometimes Newsnight, I have to say, and a lot of news shows, they have this default mode, which is: get people in, put them in the red corner and the blue corner, and make them fight." None of it, as he pointed out in his own blog (in a post now viewed over 12,000 times), "is any good for the national conversation".

Take an exchange he recently had with Labour MP Tom Watson, about whether or not, and how, Tony Blair should be questioned on the Iraq war. "And we went back and forth a while, and then he said, 'What would you prefer: the Conservatives?' And I realised, that's what everything comes down to, this binary choice. If you don't like Labour, you must like the Conservatives. The Liberal Democrats skew it a little, but still – that's the way that political conversation is conducted in this country."

But surely the method actually plays an important role in the culture? Other countries, where such exchanges are far more respectful, might frankly envy the fact that cabinet ministers here are regularly, and forcefully, held to account. "Look, if you have a dog, and you rattle a tin to get the dog to come and have a treat, you're supposed to sometimes give the dog a treat, and sometimes you don't. What it does is, he always comes to you, because he doesn't know if he's going to get a treat or not. But if you never give the dog a treat, it will stop coming. So I don't think that the default mode of aggressive interviewing is useful, because politicians just build a defence against it. In fact, they thrive on Today because they know what's going to happen.

"On the other hand, if you vary your approach from subject to subject, and introduce a bit of dynamics, people will come on the show because they'll have heard something they like, because it sounds more like a conversation than a university debating room. I know a lot of people who won't go on it, and they're bright people. It's just this macho atmosphere; people don't want to live in the world of The Thick of It all the time."

Although there are many who, rightly, want to know what he expected, going on Today in the first place, there are many more for whom he struck a real blow. "Hurrah!!!!" wrote a reader on the Telegraph website. "Someone has said it at last. I don't listen to Today anymore. I realised one morning that a) I wasn't finding out about issues, only how good a politician was at coping with hostile questioning and b) it was making me grumpy." Many of Linehan's 106,000-odd followers on Twitter have expressed similar sentiments.

Linehan, who once said "Facebook was just John the Baptist. Twitter is the real deal," and after our interview sends me a link to a talk entitled: The internet is my religion has crowd-sourcing, social media form. When the news broke that Osama bin Laden had been captured and killed, for instance, one of his first responses was to post a joke on Twitter: "Does anyone have confirmation that Osama was watching The IT Crowd in these home movies? Amazing if true. Don't know how to feel."

"I was on holiday and I was bored," he says now. "There's a famous joke that LA writers used to tell each other. Which is that you're walking through the Ecuadorian jungle, and you come across a clearing with a house in it. You knock on the door looking for a glass of water and the door opens and it's a recognisable, old, but still alive Hitler. And he recognises you, and says: 'I love your show!' And the moral conundrum is, do you turn him in? I just wanted to do a joke about Osama because I was so happy when they got him, I was just delighted. If you can't be happy about the death of someone who killed people for dancing, then who can you be happy about, you know? – and I just decided to pretend that my opinions of him had changed because he watched The IT Crowd." Trouble was, thousands believed him; it trended in the UK, and some sites began reporting it as fact. He couldn't resist adding to it, involving a friend in the US who said he had seen it on CNN …

Finally, after two days, he decided to knock it on the head with as big a joke as he could muster – both so followers could recognise it as such, and so they didn't feel too let down. He pretended to have got hold of a clip of Osama watching the video: "My heart is in my mouth" … and then "It is 'Big Bang Theory'!", a US show, also about computer nerds. "Why was it reported as 'It Crowd'? Fucking Osama. FUCKING ROT IN HELL, MOTHERFUCKER! #OBL #itcrowd #bigbangbollocks."

He doesn't just use Twitter for comedy: when, in 2009, MP Daniel Hannan used various appearances on US talk shows to denigrate the NHS, Linehan started a Twitter campaign (#welovetheNHS) which went viral.

As an evangelist, an entirely enthusiastic adopter who not only cast extras for the new series of The IT Crowd from Twitter, but found writers for it too, ("people were making me laugh regularly. And I just said – look – have you ever thought about writing comedy?") he has little patience for people such as the comedian Stewart Lee, who recently wrote a jeremiad against the internet's effect on work like his, and announced his fixed intention to write a show that resisted all that: "You can't tweet it, or trail it, or chop it up into content."

"I love Stewart," says Linehan. "I think he's a brilliant comedian. But the thing that annoys me slightly about comedians and commentators, complaining about Twitter is basically they're saying: 'Only I'm allowed to have an audience. That's how it's always been. I get a microphone, I put in the hours, I only get an audience. You're not allowed an audience.' But now everybody has a chance to be a creator, everybody has a chance to be amusing, everyone has a chance to share interesting stories, to be a journalist. You don't have to get an OK from John Humphrys to get word of something out. And this is why people like him hate it. Because you're just ordinary people – you just shut up – you know?"

Linehan could not have been more ordinary when he broke into television. Unlike the impression, easily formed, that an apprenticeship at Oxbridge, preferably in the Revue or the Footlights, is a requirement for comedy success in this country, Linehan and Arthur Mathews, colleagues at a small Dublin music magazine, and then hopeful writers in a shared flat in outer London, simply sent a couple of sketches to the BBC on spec, and were taken up by Alas Smith and Jones.

Linehan was in his mid-twenties, a middle-class Catholic who lost his religion at 14: when "I was a Holy Joe, as Ted would say. But I was going through the normal things that all 14-year-old boys go through, and I was very, very upset about it, very worried, and I thought I was going to go to hell, and then one day, we had these encyclopaedias. And the last encyclopaedia was called The Guide for Parents. And I thought, 'Oh, maybe there'll be something about this horrible thing that I have to do all the time in here.' So I opened it up, got to M, saw masturbation, turned to that page, and it read, 'Masturbation: nothing to worry about, completely normal.' And I immediately stopped believing in God."

A couple of years later he realised he could make people laugh. "I used to do these debates at my school, and I just found all that kind of … boring." He puts on a deep, portentous voice. "'Prove that religion is a force for good' – I just thought: 'I don't really have an opinion on that, so I'll just tell jokes. You know?'"

When he and Mathews met, the latter, 10 years older, was already using the Father Ted figure in his standup. The first series was not particularly well reviewed, but later, of course, the story changed dramatically: Linehan, who a couple of years ago received a standing ovation along with a gong at the British Comedy Awards, is very keen to point out that, "I always feel bad about that, because really they were standing for Father Ted," and thus for Mathews as well. There is real melancholy in his demeanour when he describes them drifting apart. They wrote separate shows: Black Books, in his case, with Dylan Moran, Hippies in Mathews' case, but when they came together again, the chemistry was gone. "We couldn't find the old people that we were. We couldn't do it – it had just disappeared. It was really sad. I would have written with Arthur forever. Writing with Arthur was like: we would come into work, sit down, laugh for the whole day. You know? And it's hard to get giddy off your own company. So I sit upstairs and procrastinate as much as I can, and then when a deadline is coming I panic and manage to write it."