IT'S one of the biggest roles in opera and it's certainly the biggest role of Ian Storey's operatic life so far.

In December, Ian will be opening the season at Milan's world-famous La Scala Opera House as Tristan in Wagner's Tristan und Isolde, playing to conductor Daniel Barenboim, having secured the role after what Ian describes as "the shortest audition in history".

He is still reeling from the speed at which things have happened and last week, left his Herefordshire home for Milan, where he will spend the next six months in preparation for opening night on December 7.

When he took a call inviting him to sing Beethoven's Ninth Symphony with Barenboim, he had no inkling of what lay ahead, only concern about the logistics of accepting.

"The one problem was that the performance was on April 23 and I had a rehearsal on April 24. No problem, they said, we'll just have to look at flights'. I thought they meant flights to Milan, but it turned out the performance was in Accra, Ghana, as part of the country's 50th anniversary of independence.

"Barenboim liked what I did in Accra, then came to see me singing Jenufa at La Scala. After the performance, I was called to the stage and asked to sing a few phrases. I sang for about 15 seconds, and he said Let's go and work together'.

"Forty-five minutes later, he said It's like I thought. He's my Tristan'. I was completely stunned. Not just by the enormity of the role, but by the enormity of the event, opening the season at La Scala."

Uniquely, Ian is being coached in every aspect of the role from scratch. "I don't know of anybody who has done it like this for one of the major roles," he says.

"La Scala are taking care of everything for me for the next six to seven months, providing me with an apartment in Milan, organising a German coach to coach me in the text of the part and to teach me to speak German."

And James Vaughan, head of music at La Scala and a world-renowned specialist in German music, has cleared his schedule to work exclusively with Ian.

"With a big part, a lot boils down to personal contact and understanding each other equally. It is just amazing working with Barenboim.

"In those first 45 minutes working with him I fell in love with him, as if he were a particularly kind uncle. He has this capacity to get you to do things you didn't think you could do. He is nothing short of a genius.

"Tristan is one of the biggest roles you can do," says Ian. "Where I might sing for a total of 40 minutes in other lead roles, there are two-and-a-quarter hours of singing in Tristan," says Ian, whose Isolde will be sung by Waltraud Meier "the goddess of Wagner".

Strictly speaking, it will not be the first time Ian has played La Scala, but it will be the first time he has sung in the main house.

His debut at the opera house took place in their alternative venue while refurbishment was under way.

"It is a huge deal, the opening night of the season," says Ian. "Tickets cost 2000 euros each and the audience will include big names like Sophia Loren and presidents."

While friends have suggested that perhaps it might have been prudent to sing his first Tristan in a smaller venue, Ian has no doubts about singing at La Scala with Barenboim.

"If you're going to do something like this, then do it with the best, though I still can't quite believe that I am going to be doing it."

And is he nervous? Six months from opening, Ian is calm personified. "Ask me again nearer the time, though," he laughs.