Heckles are to stand-up comedians what families are to Christmas — we would prefer they weren’t there, but we recognise that you don’t get presents without them. Audience backchat has always been part of live comedy, but for some reason it’s suddenly in the headlines. Two weeks ago, the former Seinfeld star Michael Richards in effect ended his career with a racist outburst on stage in response to a heckler, and reviews of Jimmy Carr’s latest live show, Gag Reflex, have focused on heckling and Carr’s response to it.

“A good live show always needs audience interaction, but there’s a big difference between people joining in for a laugh and someone saying ‘Eff off — you’re shit!’,” Carr says when I talk to him at his pre-gig hotel. “They need to be dealt with in different ways.

On tour, you have a way of thinking that means you respond quicker than on a normal day. The downside is that when I’m touring, I’m often rude to people in shops.”

Most reviewers found in favour of Carr’s verbal swordplay, but it’s curious that they chose to highlight the heckles. Perhaps it’s because his stage persona is so reserved and condescending, or because his jokes are clearly so tightly honed — “Cats have nine lives. Which makes them ideal for experimentation” — that if he appears to go off script, reviewers find it endearing. Certainly, his icy front invites some resentment. Julian Hall’s Rough Guide to British Cult Comedy, for instance, omits him on the grounds of TV exposure — while including Ben Elton, Harry Enfield, Ricky Gervais and Harry Hill.

“With a comedian, laughter is such a spontaneous response that you either find them funny or you don’t,” Carr shrugs. “What else is there? I’m trying to give 200 laughs in a couple of hours. There’s not much else to what I do. I’ve been quite successful, and I’m very grateful for that, but I worked hard. Young comics still come up and ask if it’s true that I did 300 gigs a year when I started. I don’t think you can begrudge success if someone really works for it. But what’s true about comedians is that we’ve all got a huge hole in our personality. In a room of 3,000 people, we’re the one person facing in the opposite direction — yet we have this overwhelming desire to be liked.”

Carr’s most effective response to Hall is his book, The Naked Jape, written with a college friend, Lucy Greeves. It’s a kind of Eats, Shoots & Leaves for jokes, analysing structure, debating theories of laughter and giving tips on timing. “I never wanted to write a funny calendar or a stocking-filler for Christmas,” he says. “People are interested in language and how it works. This is a book about what I consider the most interesting area of language.”

In places, the book reads like CSI: Comedy. Carr breaks down and builds up one of his jokes — “I’m not gay. Unless you’re from Newcastle and by ‘gay’ you mean ‘owns a coat’” — with an almost scientific detachment.

Such deliberation is hardwired. Carr quit his marketing job and spent a year watching comedy before writing his first joke — choosing one that deliberately made reference to his middle-class background: “Working- class kids say they lived in the East End and there was only one way out. I grew up in a cul-de-sac. There was only one way out.”

He was signed to Channel 4 after his first Edinburgh show in 2002, although his gags have since stretched the limits of broadcasting acceptability — long before Borat, he received complaints over a joke about gypsies. On a recent gameshow, he ended one round with the line: “Our four police officers are now down to three, but, unlike the Libyan embassy, we don’t have to apologise.”

Should comedians avoid offence? “I don’t think jokes shape our attitudes,” he begins carefully. “That’s a little bit more preposterous than thinking rock’n’roll can change the world. But attempting to forbid people from finding things funny is an exercise in futility — as anyone who’s got the giggles in class and had a teacher tell them to stop will know. My rule is, never tell a joke if you have to look around and check before you tell it.”

Which brings us back to hecklers. One of his early shows contained a now famous gag about comedy causing offence. “A woman came up to me to complain after a gig the other day — quite a large lady — and she said, ‘You’re fattist.’ I said, ‘No, I think you’ll find you’re fattest.’” It has entered the cultural lexicon to such an extent that audience members now shout: “Do ‘fattist’!” “Flattering as it is that someone likes the joke enough to heckle for it,” Carr says, “it might be more fun for everyone else if they didn’t request it by shouting out the punch line.”

For tour dates and information on The Naked Jape, visit www.jimmycarr.com