By David Willey BBC correspondent in Milan

Opera lovers in Milan are up in arms over the rebuilding of their beloved opera house, La Scala, which began exactly one year ago.

The facade of the theatre is now boarded

There was a serious fire risk, and the stage was too antiquated, the authorities said.

Today 60% of the area covered by La Scala has been demolished; and where once the orchestra tuned up, there is a gaping hole.

The theatre is due to stay closed for another two years, and then it will reopen in December 2004, when the work has been completed.

'Awful'

Some people here worry that when it reopens, it won't be the old La Scala that they knew before, and that the acoustics may be different.

The bulldozers have moved in to destroy one of the best opera stages in the world Giovanni Morgante, architect

"I think it's awful. It's awful because we should have conserved the old theatre as a historical monument, as a historical memory - as we keep the Colosseum," one woman told me.

City council members who demanded to see the damage for themselves later described what they saw as "worse than the destruction caused by Allied bombs during World War II".

Officials assured me that everything is going to plan. But local environmentalists are scared at the scale of the destruction of the stage machinery.

The stage machinery has all gone

Architect Giovanni Morgante even took the Mayor of Milan to court for keeping the rebuilding plans secret.

"The bulldozers have moved in to destroy one of the best opera stages in the world. It was the pride of La Scala," he told me.

His daughter Katerina - also a practising architect - told me of her shock as well.

"If you destroy the walls, a kind of spirit of the theatre is lost... If you empty a building, and you build something new, it's something different."

Acoustic fears

A brand new theatre, the Arcimboldi, has been built in Milan's northern suburbs, and this year's opera season is being held there.

All the gold will be restored, says conductor Riccardo Muti

Acoustically, it is quite adequate. But it lacks the historical connections of La Scala, where so many classic 19th and 20th Century operas had their premieres.

La Scala's Musical Director, Riccardo Muti, is in favour of the rebuilding, and thinks that in the end it will be generally welcomed.

"You must not forget that the theatre has been restored and rebuilt since the 18th Century, many times," he says.

"The hall has not been touched, but will come back beautiful. And all the gold will be restored - everything will be restored. And the stage will be a stage for 2,000 years."

He points out that the main opera houses London, Vienna and Munich have modern stages, enabling them to do more productions.

I asked him if he shared the fears that the acoustic qualities will change.

He answered: "No, because the volume of the stage will remain absolutely the same. Actually we will try to make better the acoustics of La Scala."

Muti is among the world's most renowned conductors, and the new theatre has been receiving good audiences despite its location far from the city centre.

But the jury remains out on the wisdom of knocking down most of La Scala. Only in two years' time shall we know what has been lost and what has been gained.