The Brits storming Broadway

Arcadia, considered by many to be Stoppard's finest play, is concerned with science, romance and verbal dexterity. Septimus Hodge begins as a debonair chancer happily seducing the married Mrs Chater and ends as a man whose heart and mind have been awakened. 'It's a gift of a role,' says Riley. 'Having to go from cheeky to someone who's had his whole world rocked by this person he didn't realise he was looking for... I found that very moving. As I told Tom Stoppard, Hodge was a dude.' He puts on his learned playwright voice: ' "Yeees, good, I hadn't thought of that, he is a dude,"he replied.'

Riley is one of three British actors in the Arcadia cast (Lia Williams plays the art historian author Hannah Jarvis, while 19-year-old Bel Powley is Thomasina Coverly, Hodge's precocious pupil) and their success has added fuel to the fire of the 'British invasion on Broadway' debate. Riley admits there are quite a few of them around. 'I bumped into Felicity Jones in a hotel the other day. I think one of the reasons we do so well out here is because we're so easy-going. They think, "We'll put an English guy in the lead because he's not going to complain." ' Another reason offered by the impresario Sonia Friedman is the British system of theatre subsidy, which has fostered many innovative London companies, whereas there are no native subsidised companies in New York.

Daniel Radcliffe, who made his Broadway debut in 2008 with Equus, is currently starring in the musical How To Succeed in Business Without Really Trying. Meanwhile, both War Horse and Jerusalem, which began their lives at the National and the Royal Court respectively, opened in New York this month and the former has just been granted an indefinite run at the Lincoln Center. In fact, New York's big shows have become so Brit-dominated in recent years that the oft-used phrase 'Brits on Broadway' has started to be uttered with a hint of resentment. It was last year's Tony Awards that really confirmed the phenomenon: Menier Chocolate Factory productions of A Little Night Music and La Cage aux Folles won four awards between them, while Red, a play about Mark Rothko starring Alfred Molina and Eddie Redmayne, performed an all-out board-sweep with six, including best director for Michael Grandage. Arcadia may well do the same this year: its director, David Leveaux, has already been nominated for two Tonys for previous Stoppard productions on Broadway - Jumpers and The Real Thing.

David Turner, who plays alongside Riley in Arcadia as the cuckolded Ezra Chater, was recently asked which was better, the cast's British or American contingent. He had this sardonic reply: 'Well, of course, the Americans are better because the British people, they're not good with words. See, Americans are weaned on Shakespeare, you know? British people are sort of just learning about that.' But Riley has another theory: 'What we sell to the world very well are both ends of the spectrum. Occasionally someone who's just kind of regular cracks it but generally you're either a hard nut or posh. They do like a bit of posh. But I,' he hastens to add, 'don't have a bone of posh in me.' Riley grew up in Maidstone, Kent, in a family that had 'no connection' to theatre. 'My dad's a chartered surveyor and my mum's a primary school teacher, but at four or five I said I wanted to join a drama group and started writing plays.' He studied English literature at Birmingham and graduated with a First before going on to LAMDA. After finishing in 2005, he had a dizzying start to his career when he was cast in the thriller A Few Days In September, alongside Juliette Binoche and Nick Nolte. Since then, he's had a steady stream of jobs (medical drama Monroe opposite James Nesbitt, last year's A Bouquet of Barbed Wire and Mr Wickham in Lost in Austen in 2008) but you probably won't realise how many things you've seen him in: he has the sort of features that can look unassumingly bloke-next-door-like one moment and then rearrange themselves into something fiercely, intently handsome the next.

He's six years into his career now, but is still marvelling at his good fortune, particularly the pleasures of New York, the greatest of which, Riley admits, is food. His favourite find so far is Marlow & Sons, a small restaurant in Williamsburg where he celebrated his 30th birthday a couple of weeks ago. 'It's a tiny little place, there are only six things on the menu and they change every day. They had us in a trailer out the back and I just plugged in my iPod and it was great.'

I ask him what his greatest strength as an actor is. Screwing his eyes shut and running his hands through his hair, he says: 'Oh, that makes me really uncomfortable. In America they go, "Well, I'm a whizz at acting and I have a terrific behind and it looks great for butt shots in the shower."Whereas I am more like,' he adopts a pathetically meek voice, 'OK, I know where my mark is and I can stand still and remember my lines.' He thinks some more and, eventually, has an answer. 'I think just a willingness to try anything... all I want to do is follow good work, whether it's here, there or wherever. I really want just to keep going until I'm proud of myself.' ES