Greg Davies is a God in our house. As Mr Gilbert, the sadistic head of sixth form in The Inbetweeners, he’s teenage idol heaven.

As the harassed dad in surprise hit sitcom Cuckoo, he evokes national parental sympathy, and as a stand-up he makes us roar with universal laughter. Full house.

But with such complete comedic domination there is little need for him to then embark on a 48-date tour of the country with his enigmatically titled The Back Of My Mum’s Head.

“No, but I love it. Stand up is the most exciting thing in the world. And the last tour was 115 nights so this is quite civilised really.

“Besides, if I don’t do the show I’d just walk around my flat singing and talking out loud, because I have to splurge this stuff or I’d physically injure myself. I just have to get it out.”

Even so, you wouldn’t think Greg has time either, but with The Inbetweeners concluded and Cuckoo series one done and dusted, the tour’s timing actually suits the 43-year-old down to the ground. “Just because I’ve had a good year, there’s nothing I like better than a good whinge, the classic whingeing of a middle-aged man, which I get to do on stage. It doesn’t make for a good evening saying I’m really enjoying my sitcom and have nothing to moan about.”

And Greg is making the most of it, especially as he was such a late starter. He was a teacher until just a few years ago, when he jacked it all in for life as a stand-up. So what took him so long?

“I always had a burning desire to do comedy. It was all I ever wanted to do. I just got to an age where I couldn’t put it off any more and if I didn’t get on with it I would be a teacher for the rest of my life. It was a bit of a early mid-lifer really.”

Not that it was straightforward transition, even for someone as seemingly thick-skinned as Greg.

“Stand up isn’t easy at all. It’s really difficult, so it’s a real test of your heart and nervous system. But after the first couple of years I thought ‘I need to stop feeling sick’ so now I manage to be merely agitated. If you really want to do something you can do it, but it’s never easy and often unpleasant,” he says in that famous deadpan manner.

Ironic then that his most famous TV character Mr Gilbert is in the same line of work. “People always ask me if I taught like him, and I say. ‘Of course not, Mr Gilbert is a psychopath.’ You can’t play more of a lunatic than Gilbert. He really is a terrible bully.”

Still, teaching must have kitted Greg out with some practical tools for the acting profession?

“Well, it gets you used to talking to an unwilling crowd,” he smiles. “And while acting is quite new to me, I did drama at university 20 years ago and I taught it.”

Amazing then that The Inbetweeners was his first real acting job. “Yes, sorry to all the proper actors,” he quips. Does it mean his teenage fans’ parents don’t have any idea who he is? “No, the parents watch it too, gleefully,” he tells me.

And what of all the hype and backlash around the content and language?

“I don’t think there’s anything in The Inbetweeners that wouldn’t be said in any playground, so there’s nothing shocking in it.

“It’s written by middle-aged men and I’d argue that’s why its such a success, because it taps into a national innocence. So while there is swearing and bad language there is also a real innocence there which we crave. It’s certainly nothing worse than when I was at school.”

But back to the show, which is all loosely based around a photograph of his mother.

“Yes, we were on a day trip to the Welsh coast and when the pics came out there was this one of the back of my mum’s head and it made me laugh my head off every time I looked at it. So its an evocative title and a good starting point to the show.”

And what of the content?

“There are lots of things which fill up my stupid little brain, but I start off with things that make me laugh.”

Famously close to his family, his father featured heavily in his last tour, so now it’s his mums turn.

“Dad rang me last week actually and said ‘I don’t seem to be making much of an appearance in this one’,” Greg laughs, “which is nice. but he dominated the last one. And mum wasn’t pleased because she was about to have her hair done.

“But the basis of the show is about how you feel when you reach adulthood and how aware you are of your parents. I’m offering up the hypothesis that there is no such thing as a normal person and that when you become an adult you just suppress your behaviour. It’s like a modern day Noah’s ark.

So nothing too controversial then?

“The secret to comedy is that you have to be honest and find the things that you talk about funny.

“I don’t have to set myself boundaries. I just do the things that I find funny so it’s not an issue for me.”

And then he pauses: “I won’t tell you anymore though – you’ll just have to come and see it.”