You'd have forgiven Barney Clark if he had been even a tiny bit afraid of playing the most famous of child parts in Roman Polanski's £33 million adaptation of Charles Dickens' Oliver Twist. But the 12-year-old from Hackney, London has taken it all in his stride. He's already got screen credits to his name after playing Bill Nighy's son in Brit drama Lawless Heart, while his TV credits include Foyle's War and legal drama The Brief. But even he admits that Polanski's ban on chocolate was worth playing Dickens' wide-eyed waif.

Were you amazed by the long process of auditioning for the role?

It was interesting because there were 800 boys up for the part at first and it got down to the last two and we went for a screen test in Prague and met Roman.

What was it like when you met him?

He was really, really nice but he was mainly focussing on his Oliver and what he wanted him to be. At the end of the screen test, he said, "You do know that you won't be able to eat any sweets or chocolate" because he wanted to keep my face hollow. I obviously snuck the occasional sweet in there! But to make up for it, he did let me go go-karting while filming.

What was it like filming on such a huge set?

Well, it was the biggest outdoor set in Europe, so it was amazing. I didn't feel like I was the main character when I was out there. I thought of it as just as a working job. Roman made me feel really confident about myself. Everyone was telling me he was such a legend but when you actually meet him, he doesn't make you feel like that at all.

Did he have any special tips for you?

He taught me how to cry which Oliver has to do a lot. You have to think about something really sad and try not to cry. Obviously the makeup guy helped by blowing a bit of peppermint powder into my eye. Roman said they do it in Hollywood all the time! But this Oliver is a lot braver than all the other Olivers. He fights through life and has a strong spirit. I think it came naturally as I'm not that much a shy character.

He's also got a bit of a Brummie accent...

Yeah, he's got a West Midlands accent. I think it was the dialect coach's idea because Oliver really does walk seven days to London, so where's he really from? It came really easily to me.

But you weren't like Sir Ben Kingsley and kept in character all the time?

Nah, because that would be really boring. I'd just be walking around all the time, crying and falling over himself.

What was Sir Ben like during the filming?

I only saw him as Fagin. I never saw him as Ben apart from at the parties and the screenings. Fagin was a really nice villain!

But were you ever scared of the real villain, Jamie Foreman as Bill Sykes?

He's a really nice guy but a bit scary. When the cameras were starting, he'd sometimes turn into the character and just scream and start roaring. It was quite funny. You'd laugh and then he'd just stare at you.

What was your favourite moment during the making of the film?

On the roofs with Jamie at the film's climax and doing my own stunts definitely. I love doing that kind of thing. At home I'm always riding my bike into walls and jumping off before I hit!

Oliver Twist is released in UK cinemas on Friday 7th October 2005.