When Victoria Coren Mitchell (or Victoria Coren as she was then) was asked to helm the pilot of a strange little television quiz show called Only Connect, she was outraged.

“‘No,’ I said, ‘I don’t want to host a quiz, I’m an intellectual!’ I shouted. ‘Not a quiz show host! I’m going to write novels. I’m not Lennie Bennett [the acme of TV presenter cheese].’ So I said rather loftily that, ‘OK, I will host the pilot, but I’m certainly not doing a series.’”

If this makes Victoria Coren Mitchell sound like a bit of a madam, then it shouldn’t because she isn’t. She’s a hoot, a good laugh, voluble, friendly, self-deprecating, but not in a “look at me, aren’t I being self-deprecating, please love me” kind of showbizzy way.

Her Only Connect introduction is a story she tells against herself because her love for the most curious, adorable, clever and just weird quiz bloomed instantly. “Of course, I did the pilot and was absolutely hooked immediately, I loved it. When it went to a series, I was scratching at the door to be let in.”

This was back in 2008, when Only Connect, where teams must spot the most abstruse, abstract connections between subjects, found a niche on BBC4. It was quickly discovered by an audience whose devotion became bottomless. Come 2014, Only Connect was considered such an off-kilter hit that BBC2 plumped up its cushions and Only Connect made itself comfortable on Mondays at 8.30pm after University Challenge – with audiences topping two million. Its 12th series starts this week.

Coren Mitchell describes the Only Connect world as “strange and wonderful. We are celebrating an interest in knowledge for its own sake; there are millions of people who relate to that who aren’t necessarily catered for by a lot of mainstream TV.” And she’s a magnificent cheerleader for the contestants. “These are people who are not just clever enough to answer the questions, but also people who are game enough to come along to play just for the hell of the thing. It’s wonderful and very heartening to think there are so many people like that.”

Only Connect’s devotees, including me, love it for its very Only Connected-ness, for the lack of hugging and crying, for the cleverness of its contestants and for Coren Mitchell, the slyest, funniest host nonpareil. She IS Only Connect, a woman so clearly happy and comfortable in her own skin, who 
presides over our odd little world just by being herself. Not that she was always like that.

“My Only Connect personality isn’t put on, it’s definitely me. I’m 40 – when I was on television at 25 and 30, I didn’t know who I was supposed to be. I pretended to be like other people on TV but I absolutely failed. I couldn’t do it.”

Coren (daughter of the late, dearly missed satirist Alan and younger sister of scrappy food critic and yes, TV presenter, Giles) did a smattering of poker programmes (she’s a world-class player), and would grace the occasional chat show.

“I wasn’t very good. But now I’m old enough I just go on and be me. I can be a bit weird, cross when I’m cross, tired when I’m tired and hungry when I’m hungry. That’s fine, people go along with it.”

We even went along with what appeared to be the most extraordinarily protracted pregnancy during the last series. (Coren Mitchell and her husband, comedian, actor and comedy panel-show stalwart David, have a one-year-old daughter, Barbara).

Coren Mitchell roars with laughter. “As far as the viewers were concerned I was nearly nine months pregnant from September to March. I must have looked as if I had the gestation period of an elephant.” In fact, most of the series was filmed over a very brief period, when Coren Mitchell was about eight months pregnant.

Not even that ridiculously tiny plinth she stood behind to present the Connecting Walls round could hide her blossoming figure. “I asked the team if they could find something I could stand behind so the audience didn’t see anything. But when I got there it was the width of a microphone stand and I ballooned out on either side. I was SO obviously pregnant, I was huge.”

Coren Mitchell recognises herself in her guests because she, too, trod the Path of the Nerd. And “nerd” here is a reclaimed and joyous word. “There are people who would proudly say they are nerds. When I was at school I loved maths and read lots of books and was horrified at the idea of having a boyfriend... I was probably a nerd, but then it was a negative term. Now you try to say it positively.”

She describes herself as “quite a strange, quite serious, quite bright little girl. I remember I had a copy of David Copperfield that I lugged around at primary school. I started reading it when I was seven and I was eight when I finished it. I read an awful lot as a little girl, and played games and imagined lots of things.”

At Oxford University, where she read English, her friends were the sort of people who now make up the Only Connect teams. “The quizzers who come on are definitely people I would be friends with if I met them in different circumstances.”

Coren Mitchell never sneers at anyone. A bit of light joshing, maybe, but it’s larky and kind. “There’s a sort of tradition when you have a quiz where the people taking part aren’t famous and it’s a traditional vibe that the host is friendly and a bit patronising: ‘Hello, and where have you come from and have you got a funny story?’

“There’s a big divide, sort of, ‘Ooh, look at the people who have come along to play.’ But Only Connect is absolutely not like that, it is its own complete world. Everybody on the teams, the crew, me, the question-setters, the producer – we are all on the same side. I hope the viewers feel the same way.

“We exist as a counterpoint to another sort of television where everybody wants to be a pop star and they’ve all got hair and nail extensions and they have a frame of reference that is understood only by each other. We, the Only Connect family, find that baffling. We are the kind of people who might turn up for an audition on The X Factor and be the one where they play funny noises over the top because we’re wearing a weird jumper.”

Could it work anywhere other than Britain? Probably not. “It’s quite British and the British are terribly quizzy. We’ve got the biggest vocabulary of all the languages and a huge cultural frame of reference for such a tiny country.”

No one wins a toaster or a cuddly toy on Only Connect. No one wins anything at all. “There are no prizes. Teams come along for the purity of the thing. A question unanswered is like a wonky towel, troublesome. They are there to answer those questions and if they don’t answer them and the other team does, they are so happy.”

Coren Mitchell starts and ends the show with bizarre little homilies that are all in her head, as she can’t read an autocue. “I’m too short-sighted, too squeamish for contact lenses and too vain for glasses.”

Is she beset by weirdos? Does she get strange mail from sweaty men? No, not on Only Connect, though “When I was in my 20s I wrote a weekly column for The Daily Telegraph and I was sent all sorts of filth by the kind of old colonels who read the Telegraph. One letter was an extended pornographic fantasy about me and the writer of the letter who proudly told me he was 90. All the rude words were in Latin.”

Such is the closeness of the wider Only Connect family, we were delighted when she and David Mitchell announced their engagement in The Times in 2012. What a perfect match. “I know what you mean, it makes sense on paper. I think both of our respective constituencies felt a bit sorry for us, that we’d missed the boat, though not with each other.”

The pair were introduced at a party by her friend David Baddiel. “He specifically said to me, ‘There’s David Mitchell over there, I think you should probably marry him, I’ll get the ball rolling by introducing you.’ I thought that was ridiculous but, a couple of hours later, I thought I probably would marry him.’”

She howls at any notion that they are a celebrity couple. “People sometimes say to us, ‘You guys really get your privacy respected. Who’s your publicist?’ And we go, ‘Our what?’ David and I have totally failed to become celebrities in the sense that now exists.”

Only Connect is 8pm Monday on BBC2