National treasure status is hard to attain – particularly in comedy, where the portly shadow of Stephen Fry has for years sat almost dictatorial on the throne. Slowly but surely though, David Mitchell is growing in authority; when he speaks, vast throes of the nation don’t just listen, they agree.

Having recently turned 40, he is now the very image of Grayson Perry’s ‘default man’: white, middle-class, middle-aged and – despite a few doubts as a schoolboy – most certainly heterosexual following his marriage to fellow TV personality Victoria Coren.

The advantage of this is that he can resonate with the masses, who look to him, like Fry, to not just entertain but inform, while keeping in place the very British sensibilities many are afraid of losing. He’s well-spoken, courteous and one of the only men of his stature I’ve interviewed who, upon being asked how he is, replies with a traditional English “fine thank you” instead of treating it as a journalistic prompt to talk all about his latest venture.

“I certainly write from a British point of view,” Mitchell later says of his new book, a collection of his columns for the Observer over the past eight years. “I think we’re quite low in confidence at the moment, both collectively and culturally and we feel it all the more because we were riding slightly high in the New Labour/Blair era.

“My overview about the time I’ve been writing is that we’ve been in various ways reacting to and smarting from the massive psychological blow that the credit crunch dealt us.”

Any fan of Mitchell’s work in television or print will know the score. Thinking About It Only Makes It Worse: And Other Lessons from Modern Life channels the articulate, sardonic style he has put to great effect on panel shows such as QI and Would I Lie To You, musing on everything from lasagne to the British Empire.

“In my ideal world, whenever two people met they would both just say sorry,” he writes in one article, unpacking the stereotypical English decorum that’s never been more valuable in a world still reeling from phone hacking and the MP’s expenses scandal.

With the David Cameron era evidently providing fertile ground for writers, I wonder what he makes of other comedians also getting in on the act. The Russell Brand revolution, for example, has previously drawn a passionate rebuke from Mitchell’s comedy partner, Robert Webb, but the youngest of the pair hasn’t seemed so keen to get involved.

“I don’t really want to have a public row with another comedian. I’ve got into that accidentally before and whatever’s wrong with the world, it’s not primarily Russell Brand’s fault. I think there’s a lot that he thinks should happen that I would disagree with, but it would worry me a lot more if I thought it was likely to happen!

“In the specifics of it, there’s a lot to disagree with – particularly him saying that people shouldn’t vote, which is daft – but that aside, I don’t think what he said is dangerous and the fact that he is an entertaining figure pointing out that not all is well is more valuable than it is harmful.”

It’s a noble calling, Mitchell continues, to be a comedian – “I mean I would say that” – and one that he fell in love with watching Monty Python, Fry and Laurie and Rowan Atkinson on TV. As a teenager growing up in Oxford, he was “obsessed” with comedy, yet assumed it was like dreaming of becoming a racing driver and that he’d instead end up as something like a solicitor in a “fulfilling yet remunerative profession”.

After joining Cambridge Footlights however, Mitchell met a number of like-minded people and realised his dream could become a reality. He struck up a fruitful partnership with Webb and after university, the pair moved to North London – first to Swiss Cottage, then to Kilburn – around which time they teamed up with writers Jesse Armstrong and Sam Bain to create arguably the most iconic sitcom of the noughties, Peep Show.

Next year, the show will air its eighth and final series. While sad to see it end, Mitchell and Webb are encouragingly already discussing ideas for a new sitcom, working with Veep and The Thick of It writer Simon Blackwell. Yet they’re all too aware that the possibilities of striking gold a second time are a rare thing in their business.

“It takes a lot of hard work to make a sitcom,” Mitchell explains, “but it also takes a good dollop of luck, you need it to come off. Like a good cup of tea, you know what I mean? There are some cups of tea that are amazing and some that just aren’t. It’s impossible to know whether the one you’re making is going to really come off like a Dad’s Army cup of tea or whether it’s going to be a real Brittas Empire.”

Away from his career, Mitchell’s autobiography reveals that he was often left in despair over his mid-30s bachelor lifestyle. In a crushingly romantic tale, he toiled for years over his feelings for Victoria Coren – she was at the time in another relationship – but when they finally became a couple, marrying in 2012 and settling in Belsize Park, her own family’s north London credentials further cemented it as a match made in heaven.

Having famously lived in near squalour in his Kilburn flat, his wife has clearly changed his lifestyle for the better. “I live somewhere really nice now – nice wallpaper, plumbing that works, a functioning boiler, all mod cons. I’m very grateful to her for many things, and one of them is certainly that.”

Family life for Mitchell certainly seems as content as it’s ever been, and if another project post-Peep Show strikes gold, his entry into British comedy’s elite pantheon seems inevitable.

Of course the problem with being a national treasure is that it’s a horrible phrase. No comedian in their right mind likes the term – it implies being festishised by the safe majority and Mitchell likes to throw stones at the establishment along with the best of them.

He may not be a Dickensian lothario, but then if you want to start a revolution, it’s not going to come through abolishing the vote. A world in which two politicians might greet each other by apologising, however – now that’s the sort of change I could get behind.

Thinking About It Only Makes It Worse: And Other Lessons From Modern Life by David Mitchell is published by Guardian Faber for £18.99.