'This film has been quite an education'

Dominic Cooper must have known he was on to a good thing when he accepted the role of Dakin in The History Boys but he can't have predicted just how good a great career move it would prove to be.

After a hit run at London's National Theatre in 2004, Alan Bennett's witty tale of working class schoolboys being primed for their Oxbridge exams transferred to Broadway where it scooped six Tony Awards before being adapted for the big screen.

Cooper was just 24 years old when he was offered the role that has brought him international recognition, after having impressed director Nicholas Hynter with his performance as Will Parry in the stage adaptation of Philip Pullman's His Dark Materials.

Three years on, his enthusiasm for the character hasn't dwindled and he is just as animated about playing the cocky, swaggering schoolboy as when he first pulled on his school tie and blazer.

"Towards the end of the run on Broadway I would think 'I can't do this, I just can't say these lines again'", he admits, "but we were finding things out about each of our characters right up until the last show. That's because Alan is such a brilliant writer. A long run allows you to stray from the boundaries and take more risks so you learn a great deal."

Cooper and his fellow cast members were faced with the added pressure of learning their lines under Bennett's watchful eye. The actors quickly became accustomed to the writer sitting in the corner of the room chewing on beetroot sandwiches as the cast acted out their scenes.

"Alan loved being around the set", Cooper explains, "He has a great relationship with Nick [Hynter] but he doesn't interfere. The first time I read in front of him I was a bit intimidated but that didn't last long because Alan is the least intimidating man you could meet."

Cooper attributes the play's huge success to Bennett's witty dialogue. "We knew we had a great script to work with but we didn't realise just how funny the audience would find it", he says. "There was a huge roar of laughter within a few minutes of the first night at the National. It came as a huge surprise - we were like rabbits in the headlights - but we've had that reaction all over the world."

Such humour, along with the fact that everyone can identify with growing pains of falling in love and facing up to rejection, go a long way to explaining the play's popularity. "People crave good writing which is what Bennett supplies", says Cooper.

After two and a half years of playing the character on stage, Cooper and his cast mates welcomed the chance to join the audience at the film's premiere. "I saw my character in a different light. I watched the film and thought, 'God he [Dakin] is horrible'. I was shocked by how nasty he was", he says.