Heard the one about Al Murray's split personality?

If you're going to talk to Al Murray, you really don't want to be in the front row. You really don't, for example, want to be a plump man, or an ugly man, in the front row at one of his shows. If you are, then the nation's most famous pub landlord will wrench his big face into a sneer. “Quick as you can, fat bloke,” he might yell out, or “big lump!” or “spud-faced twat!” If you're a policeman, you might be OK. If you're a policeman, you might just be told that you're “one of the ones who can read”. But you really, really don't want to be a man in a waistcoat who teaches dance.

Luckily, I am not in the front row at one of his shows, but in the bar of a very smart hotel in Birmingham. And luckily, the man sitting opposite me isn't the bullet-headed bloke with the bulldog spirit who hurls insults, crisps and his own brand of bar-room philosophy at the people who have paid to see him, but the man who, in a moment of pressure backstage in 1994, dreamt him up. This man has swapped his blazer, tie and sneer for a grey fleece, jeans and a smile. It's quite a shock, when you've been staring at footage of that sneer, and at eyes that blaze with the certainty of a bigot, to see a man who looks quite soft and cuddly. A man who might, you can't help thinking, be mincemeat in his character's hands.

He's nearly half way through an epic tour. It's epic, because it's 109 shows, which is pretty epic by anyone's standards, and it's epic in its themes, which range from parenting to the euro, 20th-century history and Scottish independence. (“If you were in a marriage where one person earned much more than the other person, and one of them had problems with cholesterol, alcohol and Type 2 diabetes, what would you do?” gives a flavour of that particular discussion.) And it's epic because it's called The Only Way is Epic, because this tour, according to the publicity, is about showing that we “can all make a difference”. This tour, in other words, even more than the other tours, like My Gaff, My Rules, …And a Glass of White Wine for the Lady!, and Barrel of Fun, is about sorting us out.

Last night was Tewkesbury, and tonight is Coventry, and Friday is Worcester and Saturday is Swansea, and Monday is Monmouth, and so on and so on for day after knackering day. Tewkesbury was, apparently, “lots of fun”. His shows, apparently, are “never not fun”. They are, he says, “always different, and always interesting, and challenging.” What he doesn't like, he says, is the travel. “There's that joke,” he says, “about the prostitute who's giving up, and she says 'it's not the sex, it's the stairs.'” Sure, I say. But 109 shows? That's a third of the year! Murray nods: “Yeah. But you can't think of it like that, or you wouldn't do it.”

Well, perhaps if you were a pub landlord, and not necessarily all that bright, you wouldn't think about the fact that 109 shows was a third of a year. But if you were, say, an Oxbridge graduate who had been making his living from doing these kinds of tours for at least a decade, you would, surely, have made a calculated decision to lead a life like this. “Yes,” says Murray politely. Which, I say, must have quite a big effect on his private life. It doesn't seem polite to mention the first marriage, which ended in divorce, and the second, which ended in separation, or the two children from the second, or the fact that all of this must involve some quite big costs. Murray skirts round it, as I think he probably will. “Well,” he says, “it has an effect on everything, obviously.”

In a recent interview, I remind him, he said he doesn't like talking about himself. Murray wriggles in his seat. “I don't think,” he says, “it would be all that interesting.” Plenty of people, I remind him, seem to think they're fascinating. Everyone on Twitter, in fact, seems to think they're fascinating. Does the fact that he doesn't think he is have something to do with his army background? With, in fact, his Lieutenant Colonel father, and his boarding school, and his upbringing in Buckinghamshire as part of a family with aristocratic roots? “No,” says Murray firmly, “it's my personal climate, or temperature. I have no great urge to write a memoir, or anything. It just wouldn't be interesting. Who cares?”

But he is, he tells me, writing a book. This isn't a follow-up to The Pub Landlord's Book of British Common Sense, or The Pub Landlord Says Think Yourself British, or The Pub Landlord's Great British Pub Quiz Book, which give a pretty good sense of the pub landlord's themes. This one is a book about history, with “lots of personal things in it”. It sounds, I tell him, just his cup of tea. It sounds just his cup of tea because Al Murray, unlike his dogmatic alter ego, has an MA in history from Oxford. He has made thoughtful programmes about German history and culture. Al Murray's Road to Berlin, and Al Murray's German Adventure, didn't, it's true, reach quite the same audiences as Comic Relief Does Fame Academy, Hell's Kitchen or Al Murray's Happy Hour. But those who did watch a bearded Murray, with hair, listening to a German choir, might have felt a shock.

“I have,” he said, “sat down to write this book about why I'm interested in history, but, like a lot of things I'm very interested in, I'm ambivalent about them. So much history is baloney, and presented as serious and important, and it's much more revealing about now, and the person who's writing it, than anything else.” He has, he says, commissioned “a big item” on it for the Today programme, which, following in the footsteps of people like PD James and Zadie Smith, he's guest editing on New Year's Day. He has done plenty of work on radio, and presents BBC Radio 5 Live's 7 Day Sunday show, but the Today programme is something else. He has listened to it, he says, since he was “tiny”. “Because I boarded,” he explains, “Brian Redhead's voice meant I was at home.”

Murray has talked in the past about how much he hated boarding school, and how he didn't have friends, and was bad at games. I tell him about a man who told me he couldn't eat pavlova because his mother used to make it the night before he had to go back to school. He was, I say, hoping to soften him into opening up, the only person I've ever met who had a Pavlovian response to pavlova. It sounds as though Murray felt the same. Didn't he?

“You can't like boarding school when you're nine,” he says, “unless you're fantastically robust and probably good at sports. But the thing is,” he adds, with just a little edge in his voice, “I'm 44 now. It's kind of not important whether I liked it or not when I was nine.”

OK. Message received. It's not quite a front-row savaging, but I'm beginning to get a sense that a real Al Murray dressing down might be a fair bit worse. Right. Back to Today. Does he think a barrage of (largely) bad news, and arguments, is a good way to start the day?

“It's very odd,” he says and he is, thank goodness, smiling again. “I love it, though, because it always gives me something to react to.” But doesn't he find that people like, say, John Humphrys, sometimes seem to be combative for the sake of it? Doesn't he, in fact, think that this kind of discussion can set up an approach to everything that's about false oppositions? His own motto, after all, on his Twitter feed, is “it's more complicated than that”. It almost seems, I tell him, to be the central message of his work.

“Well,” says Murray, who has nodded politely to my little lecture on current affairs, “it's funny you should say that. I stumbled on that earlier in the year, and one of the guys I occasionally collaborate with said, 'use it for everything', you've found the thing, and I do rather feel that. I do find the ding-dong of politics and our political discourse incredibly boring, and it plainly serves us badly as a country.” Knowing that politicians agree with each other “across the benches”, but can't admit it, fills him, he says, “with ennui”. He can't, he says, just say that “this lot are plainly incompetent” when the “other lot” are too. “I can't,” he says, “just say 'I hate the fucking Tories.'”

I tell him I practically have a breakdown every Tuesday morning when I listen to the news and try to work out what on Earth I can say about any of it in a column. There usually seem, I tell him, to be equal and opposite arguments for most things. A lot of public discourse does seem simplistic, but we have an oppositional political system. So what can we do about it?

“Well,” says Murray again, and he looks amused, “I don't think a comedian could possibly help. I find certainty, the degrees of certainty that people express, bewildering. A simple slogan like 'Save the NHS', well, you can't disagree with that sentiment. What does it mean? Which one?” No, I say, you can't disagree with that. But what comedy can do, surely, is what comedy, and in particular satire, has always done. It can, for example, puncture pomposity. “Yeah,” says Murray. And it can, I carry on, make you think, and that may be plenty, but it's surely not as good as making things better?

Murray looks a bit surprised to be told that he should be making things better. “Well, the last thing you want,” he says, “is me telling you how to make things better. I do love the thing on Twitter and Facebook when people say, 'you should run for Prime Minister'. I think that's hilarious. But the reason I went into comedy was to avoid work. To lie in in the morning, and not have to wear a tie, to essentially extend my student lifestyle.” Hmmm. That sounds like a bit of a stock answer to me. “Yes, there's the audience,” says Murray, when I tell him this, “it's a collaboration between you and the audience of where you can end up. And that was, and still is, properly challenging, but it also meant lie-ins.”

As someone who would almost rather miss a holiday than catch an early-morning flight, I can certainly understand that. But he has also pre-empted the question I haven't quite dared ask. Murray dreamt up his pub landlord when he was compering a gig in Edinburgh with Harry Hill. That was 18 years ago. Eighteen years of shows, and DVDs, and TV shows, is an awful lot of pub landlord. Murray always says he isn't bored of the character, but it's a very nice little earner, and he can hardly say he is. But he is right about the collaboration. A third of each show is improvised, and it's often one of the best bits of the show. His memory for people's names, and jobs, and his ability to draw together their stories in ways that are funny and sharp (and offensive, because the pub landlord is, after all, a sexist, xenophobic, homophobic boor) is very impressive.

One of the reasons he hasn't got bored, he often says, is because the character has developed. Certainly, in the new tour, if the DVD's anything to go by, the pub landlord is presenting a more complex range of views than ever before. “I'm going,” he says, gazing out at an audience that's waiting to be demolished, “to take you on a journey. A proper journey, like flying to Hamburg, and fire-bombing it.” And, boy, does he take them on a journey. Once his chosen victims – which, on this occasion, include a roofer, a plumber and an estate agent, which means, he says, that “we can build a house, and you can sell it” – have suffered their ritual humiliation, he tells the audience that “we've got the worst government ever”. Just when they're yelling out their agreement, he's telling them that Gordon Brown's was the worst government ever, and then Tony Blair's, and then John Major's, and then every single government going back to Churchill's. It doesn't take the audience long to realise that the laugh, after that first explosion of knee-jerk hyperbole, is on them.

Has the audience noticed the changes in his character? For a moment, Murray looks unsure. “Maybe,” he says. “Probably. They probably always did. Basically, I don't buy the idea that people have one sense of humour that reflects everything about themselves. I do get this question, 'what about the people in the audience who don't know the jokes are on them?' Well, a) I don't care, because you can't get hung up about that, because otherwise you wouldn't be able to joke about anything, and b) doesn't that make it a glorious cosmic prank that the joke's on them? I'm not going to tell anyone what to think, so I'm not going to be saying to anyone, 'by the way, you should be realising that this is ironic'. Painters don't do that. Musicians don't do that. Sculptors don't do that.”

No, they don't, and this, it's clear, is as near as the pub landlord's alter ego has got to a rant. He follows it with what's almost another one on what he calls “the debate around edge”. Sensible people, he says, say “stupid things” about “edge”. They say, he says, that “the role of comedy is to push the edge. No, it isn't! It's one of the means at its disposal.”

“Edge” may just be one of the means at comedy's “disposal”, but it's certainly a key element in his own show. When, for example, he says that “gay weddings are no one's Plan A.” He goes on to say that “homophobia” isn't the word for his views. “It's not a phobia, it's a physical reaction like dairy [intolerance].” By now, the audience is laughing at him as a homophobe, but it has already laughed at the guy in the audience who may, or may not, be gay. And when he, as an Oxbridge public-school boy, asks a sales assistant in the audience whether his father is “proud of him”, there's definitely an edge. Isn't there?

Murray looks surprised. “I suppose so, yeah, but I'm not on stage thinking of myself as an Oxbridge public-school guy. Occasionally,” he says, “I get the, 'aren't you patronising the working classes' question and then we get into the, 'alright, write me a list of what I'm allowed to joke about'.” He mentions the Twitter trial he was recently involved in, which came about when a man sent a tweet about blowing an airport “sky high”. A tweet which, it was clear to everyone except the Crown Prosecution Service, was a (not very funny) joke. On a radio discussion after, Murray met a security expert. “She said, 'watch what you say',” he says, “and you think, well, when did we vote for the Stasi?”

There is, I suggest, a safety valve in knowing that this sexist, homophobic xenophobe is being ironic, and being allowed to laugh anyway. “Yes,” says Murray. “Because comedy is a safe place. It's a place where you go to laugh, and be happy, and it's performed in a ritualised way. The amount comics have in common with priests is very interesting. We're in an intercessionary role. We lead people through a thing with a beginning, a middle and an end.” Quite where that starts and ends is, of course, another matter. At times, it's like watching someone conducting an orchestra. At times, it's like watching a TED talk that turns into a Nuremberg rally. If this is, as he says at the beginning of his show, a “journey”, it's one with a lot of quicksand, and a fair few hairpin bends.

It is funny. It is, or at least most of it, is funny. And comedians should be funny. Comedians should poke fun at stupidity, and hypocrisy, and dogmatic certainty, and this descendant of Thackeray certainly does that. “I quite like the idea,” says Murray, “of a gentleman satirist. I write a show a year, or every 18 months, and tour it. I think that's what Thackeray was doing, in a weird way.”

It sounds like fun. It sounds, but you probably shouldn't say this to a satirist, like quite a comfortable life. Most of us probably wouldn't want to give such a comfortable life up. But there's a part of me that thinks Murray could do more. There's a part of me that thinks that his pub landlord's not entirely convincing conversion to complexity is part of a bid to escape. Harry Hill, I remind him, says he's one of the brightest people he knows. Murray laughs. “He obviously hangs around,” he says, “with dimwits.”

No, I tell him, he's bright. He's clearly very bright. Does he, I ask, although I know it makes me sound like a headmistress, feel that he's made the best use of his intelligence? “Oh,” says Al Murray, and now he really does look surprised. “Oh, um, probably not.”

Al Murray will guest edit the BBC's 'Today' programme on 1 January. 'The Pub Landlord's The Only Way is Epic' is on tour (www.thepublandlord.com)