I had assumed Leslie Grantham would be monosyllabic, eyeballing me with that calm, menacing stare that the nation grew to love during his long stint in EastEnders as Dirty Den.

I also assumed he would be hard work to interview, especially with so much dirty laundry hanging out to dry. Instead, he was fresh, honest, modest, down-to-earth and friendly. Not what you'd expect from the country's favourite baddie.

What's even more surprising is that when he's at home you won't find him out boozing or having lunch in The Ivy.

Instead he's a family man, taking his kids to school, driving to football practice or doing the weekly shop.

He says: "I enjoy it actually, the dropping off and picking up, the football practice, but I get back from work at 2am and I have to be up at 6am so sometimes I feel like I've done a day's work by the time I arrive at the theatre."

Although Leslie (it's so tempting to call him Den) tells me that with three teenage sons to cope with, all of whom still live at home in Wimbledon, when he gets back from tour on a Friday night or Saturday morning he pushes open the door of the Grantham family house to find endless bodies asleep on the sofas and nothing in the fridge, "because all their friends come over too and eat everything in the house".

He adds: "My wife will go out and buy me something nice for when I get home but when I open the cupboards they're bare - no milk, no food, no tea or coffee, no nothing," he laughs.

"They still think the fridge fills itself up. Have they left home? Of course not, they've got it too good.

"Although I'll only know they've gone when I put my key in the latch and am met by an eerie silence, and you're right, I probably won't know what to do with myself."

His youngest son, Danny, has Down's Syndrome, so much of his wife's time is spent looking after him, meaning Leslie is obliged to help out on the domestic front, when he's not travelling around the country on tour.

His latest wheeze is a lead part in the hugely successful stage production of Dad's Army, in which he plays the racketeering cockney Private Walker, coming to Oxford's New Theatre on Monday.

It's a sell-out everywhere else it's been, with tickets selling on eBay for way over the asking price.

And the 61-year-old is really enjoying himself, although he says it's not exactly rock-and-roll - being one of the youngest members of the cast.

"We're all past our sell-by-date," he chuckles.

"To be honest, after the show I go back to the hotel - I share a room with 'Corporal Jones' - and we watch TV and drink a bottle of wine. But I've never been very rock-and-roll and hate the whole celeb thing.

"So I make sure I travel by Tube when I'm in London and if someone suggests meeting at The Ivy for lunch to discuss a project, I'll suggest somewhere else so that we can talk about the project rather than them staring round the room to see who's there."

But doesn't Leslie get mobbed when he goes out in public?

"No, people will come up and say 'Hello Leslie' or 'alright Den', and I get a lot of double-takes, but if you don't get out you become insular.

"At the same time it is possible to keep a low profile. I mean, it's not like I'm a Hollywood star or anything."

If you opened the tabloids a few years ago you'd be forgiven for thinking he was, such was the scale of the exposé of his Internet porn scandal, his picture glaring out from the front page of every red-top newspaper.

Leslie's second stint in EastEnders ended soon afterwards and there was great speculation that he'd been asked to leave as a result.

His ensuing autobiography Life And Other Times put the record straight in that respect - and also detailed his 10-year stint in jail aged 19 for murdering a German taxi driver. So why did he decide to come clean?

"It was more like a confession - if it was down on paper it wouldn't go away but at least it's an open book now," he explains.

"It was a bit like being a lapsed Catholic. I needed to write it."

So it was cathartic, I ask.

"No, because the monkeys are still on my back and it's not like clearing out a filing cabinet, it's still all in my head.

"But I wrote it for myself to get it out of my system. It gave me back some control and once I started writing I couldn't stop. It was like a slot machine with diamonds pouring out.

"But on the whole, I think I'm lucky, to be doing what I'm doing and enjoying it as well, which is a bonus.

"And with Dad's Army, once I read the script I realised it was still funny and what a great job it would be to do on stage.

"I did worry at first that I'd bitten off more than I could chew - did they want me or was I supposed to do an impersonation?

"In the end it falls between two stools because you can't escape the great writing but if you close your eyes you can still hear the original characters."

Does that he mean Dad's Army is enabling him to escape from his past characters for a while?

"Like that soap I was in, you mean - what was it's name again?" he teases.

"Me and Anita (Dobson) just managed to catch the nation's imagination in EastEnders and those characters tend to get remembered, that's all."