Preview: The Bartered Bride, Royal Opera House, London

For a man who is having a triumphant winter - incarnating a heart-rending Captain Vere in the English National Opera Billy Budd, and starring as the sweetly halfwitted Vasek in Covent Garden's colourful revival of Smetana's The Bartered Bride - Timothy Robinson is surprisingly diffident about his career.

But this diffidence may be the key to his remarkable ability to get under his characters' skin. "It has been an overwhelming thing," he says of Vere. "I've never done a part with so much responsibility - I feel very responsible for the show's wellbeing because Vere is the linchpin, he's there non-stop.

"On the first night, my brain started to go bananas and I made loads of musical mistakes, but I got there in the end. Playing a captain is, for me, hugely difficult - I don't feel like a person with authority. But playing the fool or a child comes naturally to me."

And Vasek, to whom the heroine of Smetana's opera is unwillingly engaged, is very much a child, who eventually finds happiness not in wedlock but by playing a bear in a circus.

Robinson admits wryly that he took a lot of critical stick for overdoing Vasek's idiocy when he originally sang the role, but points out that that's what is in the text. "Last time, we were really playing to the back of the theatre, and we're trying to do something different this time. I'd like to make my character more real." But, as he points out, the stuttering that characterises his delivery is there in the score as well. "And doing a stutter properly is a big thing!"

Robinson promptly demonstrates by clutching his solar plexus. "It takes over the character, and your physicality becomes quite big. Actually, I'd be interested to see how it came over, if you cut the stutter out completely." But not just yet.

From 6 January (020-7304 4000)