That reputation be something to do with the fact that dad Keith Allen has made something of a career of outrageous behaviour when he's not being an excellent actor - so it must be in the genes then - while sister Lily, the pop star and tabloid favourite, wrote a song about her brother's alleged drug habits.

Then there are the stories about the number of schools he was expelled from as he struggled to complete his education while struggling with Attention Deficit Disorder.

Somewhere along the way, though, he's picked up a sense of punctuality as he explains: "I don't like to be thought of as a tardy person - I'm an early bird."

And it's almost an anti-climax to discover the Alfie Allen who is now touring the country with a revival of controversial 1970s play Equus is clearly committed to the job in hand and points out that when a part and a play are so challenging, there's no time or energy left for stumbling drunk or stoned out of clubs by the end of the day.

As for the supermarket magazine headlines: "It's all press isn't it? If people want to paint an image of me then fine but I'm not going to conform to that. It makes me laugh that people want to paint that image of me.
"I think what the tabloids want to do is paint me going out and being on the lash and all that but that isn't really me. I'd rather just sit at home and watch a DVD with my girlfriend. When I do go out I have a good time but it isn't like I have to go out.

"And doing a three or four month tour of a play like Equus, where I have to be in the theatre on time every day, I guess it's going to disprove all that. I just want to focus on this and do the best I can with it."

He might be the son of showbiz parents - mum Alison Owen is the producer of hit movies Elizabeth and Shaun of the Dead - but Alfie insists that his acting career isn't simply a case of following the family business.

"It wasn't inevitable at all," he laughs. "I was into sport a lot when i was younger, though i suppose I did want to be an actor from a young age.

"Then I got a part in a film called Agent Cody Banks 2 and I just found that I enjoyed it and had always enjoyed it, even just watching my dad working, though it wasn't like going onto a set with him and saying: 'I'll do that.'

"But I think they were happy that I'd found something I loved and that I could get paid for while enjoying my work."

Peter Shaffer's Equus - a major stage break for Alfie after his recent appearance in movie hit Atonement - was written in 1973, the story of a psychiatrist's attempts to treat a young stable boy who has blinded six horses in what might be a sexually motivated attack.

The show was revived to great acclaim in the West End last year with Harry Potter star Daniel Radcliffe in the central role, a part now taken over by Alfie for the tour.

"It wasn't daunting stepping into Daniel's shoes," Alfie says. "It's a completely different production from what it was in the West End and the producers and the director made that clear from the start. I'd not seen the West End production and they were quite happy that I'd not seen it because they wanted me to bring my own thing to it."

The play attracted a degree of notoriety back in the 1970s because of its brief moment of nudity - a response that was pretty much replicated last year when it was announced that the world's most famous boy wizard would be getting his kit off for the show.

So will Alfie but he says: "I don't have a problem with it at all. I know this is going to sound pretentious but I'm in character. It isn't me taking my clothes off up there, it's Alan Strang. I hate saying that but it's the truth, that's how I think of it. It's definitely necessary to the play "

"I've never really been uncomfortable with my body - I don't think that many boys are uncomfortable with their bodies are they? I would say it's more daunting for Laura, who plays the girl, because she might feel a bit more vulnerable."

As he points out, nudity might have been a bit of a big deal back in 1973 but: "You'd think we'd have moved forward by now. But it's just as shocking now as it was then - it makes me laugh really!"