What’s eating Stewart Lee? Over the past five years, he has made himself the most essential stand-up comedian in the country, first with a stunning trio of tours that began life at the Edinburgh Fringe, then with the return this year to BBC Two of Stewart Lee’s Comedy Vehicle. It was his first big bout of television since the channel pulled the plug on his double act with Richard Herring ten years ago.

Lee, 41, has a disdain for flummery that he has turned into an art form. His Comedy Vehicle victims include nation’s favourites such as J. K. Rowling, Jeremy Clarkson, Russell Brand and Chris Moyles. And that was just the first episode. He ended a hilarious ten-minute routine on the rapper Asher D by turning straight to camera and saying, “Yes, I am disrespecting you.”

Brave? Lee insists that he’s only trying to do his job. “They just seem funny things to say,” he says, in his calm, light Midlands accent. “I’m an overweight, greying, middle-aged man in a suit that obviously needs letting out. I don’t have any power, so there wouldn’t be any skill in crushing me.”

Comedy should make fun of the powerful, he says. And that category, for Lee, includes entertainers as much as politicians. “The main thing that I hate on a daily basis is all popular culture. And the problem with the way the world works now is that you’re obliged to participate. Like if you go on Jonathan Ross, you have to sit in a room with the other people who are on it, and be polite to them. It is statistically likely that these people will be part of what is wrong with everything. And I don’t want to be in that position, because I like to be free to make jokes about their work and their attitudes.”

Lee won’t do adverts, hates doing panel shows, finds that his involved material simply won’t work at corporate gigs. And if all that makes him sound like some sort of comedy hardliner, unwilling to turn on the light lest it compromise his ability to have a pop at npower, his act is really about being playful rather than pious. Measured, rhythmic and wilfully repetitive onstage, offstage he’s looser, given to the odd gleeful cackle, yet diligent about making his point.

The television money meant he could upgrade from the one-bedroom flat that he shared with his wife, the comedian Bridget Christie, and their two-year-old son Luke, to a place with three bedrooms. He finds out in January if he’ll get a second series, enabling him to take a chunk out of the new mortgage. He started to make any proper money only three years ago, he says. Even Jerry Springer the Opera, the controversial West End hit he co-wrote and directed, earned him just £60,000 over five years.

Does he aim too high? In his last live show, he had a cheery pop at Al Murray’s populist audiences. In an interview with me two years ago, Murray said in reply: “Stewart’s very old-school BBC. He thinks there ought to be a clever person telling you how to think for your own safety.” What does Lee reckon to that?

There’s a heavy pause. “I wouldn’t have thought that five years ago. But now I think that we need some sort of counterweight to the sorts of things glibly taken as acceptable on things like 8 out of 10 Cats or Mock the Week. There’s a sort of casual homophobia that doesn’t even begin to question itself. And I think a publicly funded broadcaster has a duty to reflect various points of view. As much as the Jeremy Clarksons of this world would like to think there’s a politically correct conspiracy preventing them from having their say, they are the people getting seven million viewers. Their sort of glib, cosy, fireside reactionary attitudes are how loads of people feel.”

Lee suggests that the grateful response to his show is partly because it’s a corrective to such blather. “There’s a lot of people who are fed up with television, who are sick of feeling ashamed and offended every time they switch on. It’s not about cleverness. It’s about applying pressure upwards rather than downwards. Even a lot of shows that are really funny, like Little Britain, apply pressure downwards on disenfranchised people.”

Last month Lee made headlines because of a routine he was trying out for his new tour. Like all his material, it makes little sense in soundbite form. Say it’s about Lee wishing an explosive, painful death on the Top Gear presenter Richard Hammond, and it sounds awful. But when The Mail on Sunday asked him to justify it, he kept his counsel, knowing that the only way to defend the joke would be to explain the joke. And thus spoil it.

Now he argues it’s obvious what the routine is about: “If your escape clause for jokes in which there are victims is that ‘it’s only a joke, back off’, what’s to stop that logic being turned back on you?”

Lee grew up in Solihull, adopted by a couple who split when he was 4. He lived with his mother, but saw his dad. “I’m not one of those comedians who will tell you they did it because they were deflecting bullying or anything. I had a really, really happy childhood.”

At Oxford, he met Richard Herring. Within a few years they were on BBC Two with their show Fist of Fun. But the money they made with that got swallowed up in loss-making tours and Edinburgh debts.He feels he lost his way as a stand-up until his 2004 comeback.He and Herring remain friends, and have played a couple of benefit shows together. But a full-time reunion is out. “Now it would be like doing an act. And I can’t really act.”

Marriage, he suggests, has broadened his outlook. “I think our relationship has humanised what I do. I read things online that say I’m dislikeable and smug and arrogant, but to an extent that’s a cultivated persona. What I was doing in the Nineties, being cynical about everything, was a dead end. It may look like cynicism still, but it’s frustrated romanticism. Because you have to take a romantic view of the world as a parent. You have to have hope.”

Stewart Lee’s Comedy Vehicle is out on DVD. His tour, If You Prefer a Milder Comedian Please Ask for One, begins in Lincoln on Oct 6.