Given the subject of his latest movie, 21, takes him into the gambler’s paradise that is Las Vegas, it seems fair to enquire whether Kevin Spacey sees himself as a risk taker. Pausing for a moment, south London’s favourite adopted son shares his thoughts.

"I think coming to London and starting a theatre company was probably a pretty big risk. But as I sit here in the middle of our fourth season, about to hit our millionth patron mark of audiences that have come in, I think that’s encouraging for a fledgling theatre company."

Based on a true story, 21 follows the exploits of a brilliant group of maths students who shift the odds in their favour by teaming up to count the cards at the blackjack tables and beat the casinos at their own game. No longer active in this dangerous pursuit, some of the students accompanied Spacey on a research trip to Las Vegas, one even standing behind his chair and keeping an eye on proceeding.

"Every time he wanted me to up my bet he’d just push against my chair," Spacey says with a smile, "and I won every time. I wish they would follow me around all the time."

When it comes to his other enterprise, Spacey seems to have made his own luck though. His tenure at the long-neglected Old Vic has been a tremendous success though he was not given the smoothest of rides when he first arrived as artistic director in 2003.

"I think that’s par for the course," he says matter-of-factly. "If you go back and study the history of theatrical beginnings, as I did when I started, you would have been as prepared as I was for the critical assessments. If you go back and look at the first three seasons of the Royal Shakespeare Company, they were a disaster according to the critics. Now we think the RSC can do no wrong. But when they started they were not welcomed.

"Peter Hall had his critics; he was called a disaster in his first three seasons at the National. Even Olivier had his critics. You just go down the line and you start to realise that’s the way things have been greeted. I prepared myself for even worse, because I knew I was a film actor and I was an American and that seemed to be ripe for a sniper’s target. But actually it was less personal than I thought it was going to be. And it ended when I hoped it would.

"By that I mean when they stopped judging the theatre company, when it stopped being about my ‘rein’ and they began to judge the plays as the plays. I always knew it would take us three or four seasons to establish ourselves, and that’s exactly what happened and that’s exactly what I kept telling my staff. I said; ‘keep your heads high, we have a 10 year vision, we’ll get through this, it’s been done before’."

Recently performing in Speed-The-Plow opposite Jeff Goldblum, Spacey remains a mercurial figure in the British arts firmament. Admired for his achievements, his direct and outspoken style also touches a chord, as with his criticism of the BBC for turning Andrew Lloyd Webber’s casting sessions into – admittedly very popular – prime-time evening viewing. It underlines his passionate defence of the theatre he has revitalised, though not all his decisions have been met with universal applause.

"My task was to return the Old Vic to being a destination theatre for audiences who’d not been coming for 30 years," he explains. "Yes, there’d be the occasional hit play, but there was no audience development, no education, there was nothing like what we do with Old Vic New Voices. It didn’t exist, it was a building – with a great history, but not a great recent history.

"It’s a 1045 seat theatre, and if you’re playing under 70% you’re dead in the water, because we have no subsidy. Our risks are our risks, and if we have a show that goes down, it seriously damages us – particularly as we were just starting out. I could pretty much predict that people expected us to start with Shakespeare and Ibsen and Shaw and Chekhov. But I was fairly convinced that if I started there I would be playing to an established theatre-going audience, and that audience would be very now.

"And unless I put big stars in every show it was not guaranteed that you’d be playing at over 70%. The only way I felt to get a broader, more diverse and younger audience into that building and start to build an audience was to do work that I thought would be exciting and entertaining but maybe not what you’d expect to see on the Old Vic stage."

The new programme that Spacey envisaged included pantomime after he sounded out Sir Ian McKellen about a return to the stage, and veteran actor suggested a traditional British panto. "I thought to myself ‘what’s a panto?’" Spacey grins. "But it was explained to me and I did some research on it and I realised that the last time Aladdin was done at the Old Vic was 1860."

Whether McKellen has passed on his love of another British institution, Coronation Street, Spacey is not letting on. Like the characters he plays, certainly like the maths professor in 21, he always gives the impression of being contained and in control, with much going on beneath the surface. So however you try and ask him whether he has succumbed to the pleasures of Corrie, gypsy creams or a hitherto unsuspected passion for Millwall, he gives the impression that he calculates how the result will look in print before delivering his answer. His Anglophile tastes, he reveals, are a little more highbrow.

"I’ve definitely gotten into modern art in a way that I never really was before. I go to art galleries and see a lot of stuff. I’ve bought a few things. I’d sort of admired it before but I never really got into it, there’s just such an incredible number of places to go and galleries to see and openings. I’ve always been into the jazz scene here, on any given night I’m very happy to be cosily tucked into Ronnie Scott’s."

If Spacey has fallen for the charms of some aspects of dear old Blighty, the feeling – it seems – has been reciprocated, even when his charge of the Old Vic was subject to less reverential treatment from those who now sing his praises.

"In the face of all of that I never stopped getting letters from the British public saying ‘hang in there’, and it was always my intention to do just that so I’m glad that it’s going along alright."