CORK CITY and Gotham City may seem a world apart but for Cillian Murphy . . . real-life son of the first, make-believe scourge of the second . . . they are oddly intertwined this week. The biggest film of his career so far is about to open around the world and the 29-year-old actor is back in his hometown, staying at his mum's house. The irony isn't lost on him. Murphy plays The Scarecrow in Batman Begins, the latest instalment of an ailing franchise that needed new life breathing into it.

The man with the magic lips (or so the studio hopes) is Christopher Nolan, the British director who gave us offbeat thrillers Memento and Insomnia. He has assembled a stellar cast which includes Michael Caine, Liam Neeson, Morgan Freeman, Gary Oldman and Katie Holmes. British actor Christian Bale plays Batman. Early reports are good.

The film opens this week, and a tiny percentage of the millions who see it will pay their money at the Cork multiplex where Murphy sat recently, watching another film and enjoying his first sight of the Batman trailer. "It was the cinema I used to go to when I was bunking off college and then there I was, on the screen in a trailer in front of Star Wars, " he laughs.

Nolan originally auditioned Murphy for the lead role, having seen him in Danny Boyle's film, 28 Days Later. British audiences will be most familiar with him from that film, in which he plays a cycle courier who wakes from a road traffic accident to find that London has been taken over by zombies. Alter-natively, they may have seen him on television, in costume drama The Way We Live Now alongside Shirley Henderson and David Suchet. Either way, Murphy has one of those faces which, once seen, is not easily forgotten. Mostly this is down to the eyes, which are pale blue and piercing. But the sculpted cheekbones help.

As well as Bale, Donnie Darko star Jake Gyllenhaal was up for the part of Batman along with three others. Murphy didn't think much of his own chances but he climbed into the bat suit, anyway. "I didn't have any ambition to get the part, " he tells me. "I never saw myself as Batman material. Ever. For me it was an opportunity to work with Chris Nolan because I admired his films. Then I heard that Christian Bale had got the part and I thought it was a wise choice." Then came a phone call. Nolan had been impressed by the young Irishman after all, but wanted to use his cold intensity for the part of a boffin-turned-criminal who spreads a fear-inducing toxin round Gotham. "It's a nice role, pretty integral to the film, " says Murphy modestly. "I'd never played a baddie before and comic book villains are a part unto themselves." It's also a significant step up the Hollywood pecking order. While

he appeared opposite Scarlett Johansson in Girl With A Pearl Earring and shared a scene with Natalie Portman in Cold Mountain, those were both small parts. Apart from 28 Days Later, his biggest roles to date have come in Irish films, most recently in Intermission, alongside his old friend Colin Farrell.

Murphy mentions Farrell before I do, but their friendship is common knowledge and the Cork man has previously adopted a guarded tone when talking about the hellraising Dubliner. "I haven't seen him in ages, " he says. "I used to see him more." Like everyone else, he follows Farrell's escapades through the pages of the tabloids. "Colin doesn't seek that stuff. It's really uncontrived. That's just the way he leads his life, the way he's always been, you know? The guy is a f***ing great actor and has worked with amazing people in such a short space of time. He just popped up as this completed film star. He comes into a room and he changes the energy because he is an unbelievably charismatic individual. And you can't fake that, nobody can. As a result he sends ripples wherever he goes." And what about Murphy; does he send ripples wherever he goes? "No, and it doesn't bother me in the slightest,

" he laughs, as the waitress shoots him yet another look. Now, if that wasn't a ripple. . .

We're talking in a bar called Bodega on Cork's Cornmarket Street. Murphy had wanted to take me to Dennehy's, a classic Irish boozer opposite, but it's shut. It seems symptomatic of the new Cork that we have to forego the calm of Dennehy's for a barn of a place with an espresso machine and a chic Spanish name. Murphy hasn't lived in the city for 10 years, but he doesn't much like what he sees when he returns.

"I do feel that there is something happening over here, " he says. "When the money arrived, which it did over the last 10 or 15 years, people became slightly blinkered and hugely consumerist very, very quickly. Maybe it's because I'm at that age when you start looking at architecture, but when you walk around Cork there's so much f***ing stuff that's just thrown up. A lot of it is tax breaks for the filthy rich and they're eyesores. That sort of thing makes me angry." Ireland, he says finally, is becoming "a bit too f***ing MTVed." Perhaps Murphy is living too much in the past. If he is, he has an excuse: the reason he's back in Cork is because he's starring in Ken Loach's new film, The Wind That Shakes The Barley. The title comes from an old Irish rebel song and the film concerns the so-called Flying Columns who fought the British army in West Cork in the early 1920s. As with the last five

Ken Loach pictures, this one is scripted by Scottish writer Paul Laverty.

Murphy is glad it's an Englishman directing. "It's still a sensitive topic round here, two or three generations later, " he says.

"I don't think he'll court controversy with it but I think it will be controversial".

If Batman Begins is the film that will finally announce Cillian Murphy in Hollywood, then The Wind That Shakes The Barley is the one that will cement his reputation as an arthouse player. Loach, remember, is a firm favourite with the Cannes Film Festival selectors.

Murphy enjoys that duality and says he will struggle hard to maintain it in the teeth of lucrative, but artistically bankrupt, offers from Hollywood. "If you get a million dollars now for doing something that's shit, you just cancel out everything you could potentially do in the future. I don't think that Chris Nolan or Danny Boyle or any of these guys are going to be interested in me when I'm doing some shite teen movie in America." He's just back from the States after shooting Red Eye, a new film from horror supremo Wes Craven. It was, he says, "a very strange experience for me. But it's such an antidote to that to come and to live at home and work here. Ken Loach dispenses with all the bullshit around film-making: there's no trailers, there's no pampering, there's none of the nonsense that surrounds films and film sets. It's all about the story and the actors." He means that it's closest

in spirit to his first love, theatre. It was as a raw 20-year-old that Murphy took his first steps into acting in the play Disco Pigs, a two-hander written by Enda Walsh about a couple of wild Cork teenagers. It was the sensation of the 1997 Edinburgh Festival Fringe where it played at the Traverse Theatre.

"We had an 11 o'clock slot and it was packed every night. We got incredible reviews, awards. We were just drunk all the time. It was crazy. And it's still one of the best parts I've ever played . . . It was the experience in Edinburgh that made me say 'This is too good to give up'." Instead, it was Murphy's university career that was jettisoned, leaving him to forget about studying law and concentrate on an acting career. And even as the film roles pile up, he has continued with theatre: in 2003, the year of Cold Mountain, Girl With A Pearl Earring and Intermission, he found time to return to Edinburgh to play Konstantine in Peter Stein's International Festival production of The Seagull, at the Royal Lyceum.

Before rehearsals began, Stein took the cast to visit the Russian estate where Chekhov wrote the play. Rehearsals took place at the director's home in Umbria, Italy.

"That was one of the most idyllic jobs ever, " Murphy laughs. "We rehearsed for seven weeks in his gaffe, in the summer, then went to Edinburgh and played for two weeks." Theatre is something he will never let go of. It's the place he goes to recharge. "When it works, there's nothing like it. The whole audience is in the moment - you never get that from a film. A film can stay with you and affect you but that instantaneous magic that theatre can create is hard to beat." When I leave him, Dennehy's still isn't open. Murphy is heading to West Cork for a night shoot. He has his bag with him, an old leather satchel that he carries under one arm. We say goodbye and I walk along the Grand Parade, past a cinema which will soon be showing Batman Begins.

Examine a map of Cork and you'll see that the city honours its own. There isn't yet a Roy Keane Way but there is a Michael Collins Bridge, a Terence MacSwiney Quay and, though he wasn't from Cork itself, an Oliver Plunkett Street. A footballer, two patriots and a martyr. Cillian Murphy may have misgivings about his hometown but, if his rise and his luck continue, they may soon be naming a street after an actor, too.

Chances are it won't be a cul-de-sac either.