Rob Webb and David Mitchell seem a bit bored of Peep Show. Of course, they’d be too diplomatic to say so themselves, but after an hour’s conversation with them both, there is a lurking suspicion that they’re slightly tired of the offbeat Channel 4 sitcom that made them A-list comedians, paved the way for Magicians, their first feature film, and led to their notorious appearances in those hilarious Mac adverts.

It’s easy to see why: they have no direct involvement in Peep Show’s writing process. Sam Bain and Jesse Armstrong are the writers behind those perennial no-hopers Mark Corrigan and Jeremy Usbourne, and, perhaps most tellingly, they, not Mitchell and Webb, are the show’s Executive Producers. And, contrary to popular belief, it’s Sam and Jesse, not Rob and David, who bear the most similarities to Peep Show’s antiheroes.

“Mark and Jeremy are a little like us, but they’ve got a lot more of Sam and Jesse in them,” Rob explains. “So we’re more detached about Peep Show. Jesse and Sam talk to us at the beginning about the plot, but they still do about 98% of the script.”

Which is probably why Rob and David are so excited about the second series of BBC2’s That Mitchell and Webb Look, which started last night. Says Webb, “We inevitably feel more attached to That Mitchell and Webb Look. We feel more personal about. We write three-quarters of it and so tend to feel more rewarded when it goes well, and more depressed when it doesn’t.” Mitchell clarifies: “We’re very proud of Peep Show, but we simply have more emotional investment in That Mitchell and Webb Look.”

So what have we got to look forward to in this latest edition of the emotionally-invested, awkwardly-acronymed TMAWL? Mitchell again: “Content-wise, the new series contains a lot more stand-alone, one-off stuff. There aren’t many recurring characters and we’ve got rid of a lot of last year’s content like Big Talk and Ted and Peter, the snooker commentators. We felt those ideas had run their course.”

Hang on! Is Numberwang no more? And what of Barry Crisp? And that Chicken Salad chappie? “We’re keeping Sir Digby Chicken Caesar and we’re doing a kind of history of Numberwang in episode six, but apart from that, everything’s new. There’s one sketch about a robotic man who loses his sense of smell to the extent that he can only smell petrol and cheese. And there’s another about a film-maker who’s basically the antithesis of a dramatic director; he insists on everything being real. If a character needs to go to the loo, he goes to the loo. We’ve also got a sketch about these heli-vets.” And what are these? “Just some very bad vets,” explains Rob.

Of course, TMAWL and Peep Show aren’t their only notable projects. In 2000, they aired a surprisingly unsuccessful sketch show called Bruiser – surprising given their collaborators included Ricky Gervais, Martin Freeman, Matthew Holness and Alan Titchmarsh; from 2003 onwards, they broadcast That Mitchell and Webb Sound, the radio show that laid the foundations for many of the sketches in the first series of TMAWL. And, Webb continues, “we’re planning a pilot sitcom of our own for the end of this year. It’ll inevitably be compared unfavourably to Peep Show, but we’re prepared for that, and we’re going to try and make sure it’s as different as possible. We’ll write it in a much more fruity way. It’ll be more like Father Ted.”

Yet, slightly bizarrely, the production that really shot them into the national consciousness was not a sitcom or a sketch-show but an advert for Apple in which Webb played a Mac computer and Mitchell a PC. The pair attracted a great deal of flak for their performances; the Telegraph criticised them for seeking “corporate ends”, the British Sitcom Guide accused them of “selling their souls” whilst Nathan Barley’s Charlie Brooker hated their “smug” tone.

“The almost vitriolic reaction genuinely surprised me,” declared a surprised David Mitchell. “We weren’t advertising McDonalds or Exxon or anything like that. We were doing it for what is quite a cool company. I think people assumed that because we were the stars of Peep Show, we had a duty to be anti-capitalist.”

“And I’ve owned a Mac since 1998,” Webb interjects. “It was a natural choice.”

Indeed, the Nineties were important years for the duo, and not just for computing reasons: four years before becoming acquainted with IBM’s greatest rival, Webb got to know Mitchell through Footlights. “I spotted him at the end of 1994. I asked him if he wanted to do a two-man show, and he couldn’t really refuse because I was in the year above, on the Committee and kind of a big deal.” And, after their seminal ADC run of Innocent Millions Dead or Dying: A Wry Look at the Post-Apocalyptic Age, the pair decided to make it in comedy together and Rob “hung around eating toast until David graduated”. Their career in comedy was tough to begin with. “I once had to drive a seven-and-a-half tonne truck to pay the bills after we left Cambridge. That was horrible. And we were both ushers at the Lyric Hammersmith, which has left me with a phobia of middle-class theatre-goers.” David elaborates on their travails: “We were just putting on shows in the London fringe. We were very low on money and we had no idea how to go about finding an agent.”

Many ex-Footlighters are reluctant to lend their support to their comedic alma mater, but, to their great credit, Mitchell and Webb are quite possibly the most supportive alumni, regularly showing their faces at Footlights events and often supplying Cambridge comics with positive quotes for their Edinburgh posters. So what do they make of Mark Watson’s suggestion in Varsity last month that ex-Footlighters are somewhat stigmatised within the comedy industry?

Mitchell certainly agrees. “When I was in Footlights,” he says, “it was at its least fashionable. Rob and I had to pretend we hadn’t been in it. You’d often hear people say, ‘Oh we’re not going to see that bunch of fucking toffs,’ because they’d assume that it has some sort of nepotistic link with the comedy industry. But that’s just not true. To be a comedian, it helps to be bright and Cambridge simply has lots of bright students. I think the Footlights situation has now reached a happy equilibrium. Agents and producers will still go see the show but they won’t be biased in their treatment of it. It’s OK to be in Footlights again.” Numberwang, evidently.

That Mitchell and Webb Look in on Thursdays at 9pm on BBC2 and BBC HD.