Jason Isaacs is about to become one of the most despised men in Britain. Not personally, you understand, but in his guise as the Machiavellian wizard Lucius Malfoy, the cunning villain at the centre of the blockbuster film, Harry Potter And The Chamber Of Secrets.
On screen, Isaacs is the embodiment of Lord Voldemort's evil, single-handedly orchestrating a devious plot to bring about the downfall of Hogwarts School of Witchcraft and Wizardry, and its headmaster Professor Albus Dumbeldore. In person, Isaacs is both charming and softly spoken, and extremely self-deprecating, suggesting the reason he was cast was, perhaps, because he was the cheapest actor available.
The film's director, Chris Columbus, disagrees: "It's his eyes," he explains. "For such a sweet, good-natured fellow, on screen he's the personification of evil. You look at his eyes and I've never seen eyes that colour — they're this cool blue."
Isaacs, 39, is no stranger to movie villains. Two years ago, he starred opposite Mel Gibson and Heath Ledger in The Patriot, playing a sadistic British officer who mercilessly kills women and children, then burns down a church packed to the rafters with innocent villagers. The role brought him to the attention of Hollywood, and earned him a Best Supporting Actor nomination from the London Film Critics' Circle.
More recently, he took up arms with Nicolas Cage and Christian Slater in Windtalkers, and survived Ridley Scott's gruelling Oscar-winning war opus Black Hawk Down — an experience he compares to "lying on a bed of nails".
Next year, we'll see him starring with Jackie Chan in the action-comedy The Tuxedo, and he's just set off for Australia, to shoot PJ Hogan's eagerly awaited, live action version of Peter Pan, playing the dual roles of Mr Darling and Captain Hook.
For his role as Lucius, Isaacs dons fur-lined suits and sports a rather fetching head of waist-length blond hair. "Actually that wasn't the original idea — that was my idea, the long blond hair," the actor reveals. "I think the original idea was to have short, ruddy hair and a pin striped suit — Lucius works in government. I thought, 'Well, I'm only going to play a wizard once in my life', so I asked if I could try out with the long blond hair. They made a wig, I put it on, director Chris Columbus looked at it, and said, 'Yeah, that's better'."
The character's distinctive snake-headed cane was vital to the transformation. "I actually didn't feel like Lucius until I was holding that cane," he explains. "Without it, I felt like Iggy Pop or someone, but I soon as I got that cane, I felt like Lucius. I felt like I could do magic with it."
Villain or not, Isaacs is quick to defend his character, and even seems to sympathise with Lucius.
"He's not mean, he is just angry — I'm playing pop psychologist here. He doesn't think he's mean, he thinks he speaking perfect sense, about the Mudbloods. Then there's the other thing about him being a father — he's a horrible dad. For me, that explains why his son Draco is such a horrible at bully at school, because he gets no love at home. I can see generations of Malfoys stretching back through time: cold, brutal and loveless."
Joining a large and established cast like the Harry Potter ensemble could have been intimidating, not least with Richard Harris, Maggie Smith, Alan Rickman and Robbie Coltrane part of the Hogwarts firmament. "They were all very welcoming," he confirms. "Everybody knew what they were doing so there was a lot less anxiety on set, especially for a giant film, where people are normally quite nervous."
He speaks fondly of Harris, who recently lost his battle with Hodgkin's Disease. "I was at drama school with Richard Harris's son and Richard, with this terrifying presence, would descend every now and again to see one of our plays and we'd all need a change of underwear because the Richard Harris was in the audience.
"My first day on Harry Potter was with Richard and I'd always thought that if I ever got to act with someone like that, it would be in King Lear or one of the great classics. And instead, we're there, dressed as wizards.
"The temptation is not to take it seriously. But then you get Richard start speaking as Dumbledore. He's a very intimidating presence, and a brilliant actor, and suddenly I was there in Hogwarts, facing a headmaster who knows what danger I pose to his school."
The Chamber Of Secrets has been criticised for its dark and unsettling content, particularly the scenes with Aragog and the spiders, and the final showdown between Harry and a giant snake. British censors have passed the film uncut with a PG certificate, but some critics have questioned the film's suitability for young children. Isaacs — who is married with a six-month-old daughter — is quick to leap to the film's defence.
"The books get darker and darker," he argues. "I think this film is definitely more thrilling, I hope it's more scary because I'm in it. I think we're often too protective of the imagery we throw at children, in the sense that I think they can take far darker and more scary things than we think they can.
"There is nothing more grotesque, terrifying and nightmarish than Grimms' Fairytales, and children of all ages have read those.
"Look at what kids watch now at teatime: Buffy The Vampire Slayer — images that would have sent me to a psychiatrist when I was a kid. Creatures, with the kind of make-up that used to be hidden away on films like The Exorcist, are now on at 4pm and they're getting decapitated and staked through the heart."
He accepted the roles of Mr Darling and Captain Hook in Peter Pan before he was cast in Harry Potter, which presented something of a dilemma when he got the call to play Lucius Malfoy.
"I thought, 'I can't do it, I can't do two children's films, I'd be mad'," he explains. "Then the phone started ringing — it was all of my godchildren. They were furious, not even begging me or asking me to do it, just livid with anger, saying they would never see me or speak to me again if I didn't do Harry Potter. Partly because they wanted to see the film with me, and partly, I think, because they wanted to visit me on set.
"They kept saying, 'Think of Lily' — my baby daughter — 'she will be so glad her dad is in Harry Potter'.
"I've been thinking about it recently and I don't think she'll be telling all of the other kids in kindergarten that her dad is Lucius Malfoy. They'll scatter whenever I come to pick her up from school!"