A big-screen version of Andrew Lloyd Webber's The Phantom of the Opera is upon us. Director Joel Schumacher talks to Donald Clarke

Poor old Joel Schumacher. Though some of his films have been well reviewed - Falling Down, Tigerland, erm, that's it - he remains, Michael Bay notwithstanding, the critics' favourite whipping boy. He's 65 now. He's made a lot of money and launched quite a few careers (that of Colin Farrell for one). Doesn't he deserve a break?

"But, you see," he reasons, "when journalists, like you, say I have been unfairly kicked around then they are themselves demonstrating that I am appreciated."

Well, yes, but then I'm really just being polite (I don't say). In fact, like most people who have met Joel Schumacher, I find myself wishing his films were a little better. He is so funny, so nice, so entertaining. The former window-dresser and production designer - his shirt collar open across a tobacco-coloured turkey neck - comes across like a deliciously camp Native American retiree. It's a shame that somebody so endearing should be responsible for such unlovely projects as The Lost Boys and Batman & Robin.

Andrew Lloyd Webber - unlike Joel, rarely celebrated for the warmth of his personality - has had a similarly torrid time with the critics. So, in some perverse, sod-you sense, Schumacher was the ideal candidate to direct the big-screen version of His Lordship's theatrical phenomenon, The Phantom of the Opera.

"I read an interesting quote the other day about Andrew," Schumacher says. "'Nobody has ever liked Andrew except the public.' Well, isn't that the idea? Are we supposed to be doing these for the critics or the audience?"

Fair point. Though high-brow pundits have had scarcely a good word to say about it, The Phantom of the Opera has, since its première at Her Majesty's Theatre in 1986, gone on to become a formidably rapacious industry. Productions have been mounted in over 20 countries. Seventy million people have, between them, paid over £1.6 billion to sit through the blasted thing. So why has it taken so long to reach our screens?

"Well you'd have to ask Andrew," Schumacher says. "He first asked me to do it when it opened about 16 years ago. I was just beginning and he was a legend. He loved the way music was used in The Lost Boys and offered me the job."

The first delay occurred when Lloyd Webber and his then-wife, Sarah Brightman, who originated the role of Christine, the Phantom's frail protégé, decided to divorce.

"So we put it on hold while they sorted out their lives. Then my career unexpectedly took off. He asked me again over the years, but I was always just so busy."

Throughout the 1990s, in between various Batman spectaculars and John Grisham adaptations, Schumacher remained friendly with the now ennobled Lloyd Webber and his current wife, Madeleine.

"The Lady Lloyd Webber has a very strong personality," he says archly. "She was determined that I was going to do it. I had turned Andrew down a hundred times. I was just too busy. A mutual friend who was very wise - I found out later that she had been cleverly enlisted by Lady Lloyd Webber - said, 'Before you say no again, remember why you wanted to do it in the first place.' That was good advice."

Throughout the 1990s, as the project meandered through development hell, speculation concerning casting abounded. Phantom fans, like Dr Who enthusiasts, take the object of their obsession very seriously and, accordingly, a great deal of furore accompanied the news that Michael Crawford, the first Phantom, was no longer being considered for the title role in the film. Many names were bandied around, until we ended up with Gerard Butler, star of Dracula 2000, and Emmy Rossum, Jake Gyllenhaal's girlfriend from The Day After Tomorrow.

"I thought about it a lot and I said to Andrew, OK, I will do it, but only if the three leads are young. Christine is so innocent and so haunted by her father's death, they just won't buy it unless she is a teenager."

How did Lloyd Webber take the ultimatum? "You have to remember there is a 16-year friendship here and a great deal of trust," Schumacher says. "He said that was fine, but they must do their own singing. And I thought that was fair. Look, there were a lot of movie stars who wanted to be in the picture and I didn't want to have a middle-aged Phantom."

It has been suggested that Lloyd Webber was, when Schumacher came back on board, still keen on casting Antonio Banderas. The Spaniard's name had been mentioned in association with the role for years.

"I don't think I should mention any names because that wasn't really on my watch," Schumacher says. "That was all before I came back to the project. There were other stars too. I know there was one person in particular who was campaigning very heavily for it. I thought that, since Emmy was 15 when I cast her, it wouldn't have been right to cast a 51-year-old. It would be just like Lolita." (Let us casually mention that John Travolta, who will shortly be 51, was talked of so frequently as a potential Phantom that some pro-Crawford Phannies went so far as to set up a No Travolta website.)

Schumacher's decision to keep the cast young makes sense, but Rossum really was little more than a child when she secured the role. This sounds like a sizeable gamble. "Oh, there's always risk. But, you know, the Good Lord has always been kind to me with unknowns." Like Colin Farrell, the then-unfamiliar star of Tigerland?

"Yes, I have heard of him," he laughs. "Emmy was already a star in that she had been singing at the Metropolitan Opera House since she was seven. Here she was: drop-dead beautiful with her gorgeous skin and her eyes and, oh, that neck. She spoke so beautifully and then I discovered she was a singer. It was like I had ordered someone from a catalogue. But you know Michael Crawford was known for being a sit-com star, and Sarah Brightman was a dancer in Cats. So they were unknown in this field."

Whatever else you may say about it, Schumacher's Phantom is carried off with great technical aplomb. It must have been quite a jolt moving from Veronica Guerin, his passable 2003 biopic of the murdered Irish journalist, to this complicated, flashy fantasy. Did he have to learn new skills?

"Yes. And that is why I did it eventually. It was just scarier than all the other movies I could have done. If I am not doing something that scares me then I am not doing the right thing. I had never done a musical before so that was very scary."

Schumacher still seems energised by new challenges. But having, after two decades of furious activity, just joined the bus-pass generation, perhaps he should slow down a little. He looks astonished. "But I get all these wonderful opportunities. What would I do with myself?" Well, it would, at least for a while, get him out of the eye-lines of ill-spirited critics such as myself.

"Oh, I think I'm treated fairly," he says. "I have caused a lot of trouble with my movies on purpose. But people love my movies. They connect with them. I think I am one of the luckiest people on the planet.

"Movie blockbusters are, to use a Hollywood-friendly analogy, rather like earthquakes. Some time after the initial tumult a series of further shudders - some major, others barely noticeable - will manifest themselves. Nervous citizens may come to fear a permanent change in the seismic anatomy of their locale, but soon enough the subterranean plates will settle themselves back into uneasy equilibrium."

The Phantom of the Opera opens today