I first met James Nesbitt eight years ago when I accompanied him on a trip back to his home town of Portrush, an hour west of Belfast, for the filming of an episode of the drama that first made his name, Cold Feet. It was a revelatory experience; up until that point, I had never truly comprehended the meaning of the term "local hero".
One minute, Nesbitt was taking calls from the mayor begging him to attend a grand ceremony to accept the freedom of the city; the next, he was being bought a seemingly endless supply of drinks at the jam-packed Harbour Bar by the ecstatic regulars, every single one of whom claimed to be "a friend of Jimmy's". Never has one man posed for so many photos with so many random strangers. Eventually, the attention became too overwhelming and we had to bail out of the pub.
The mêlée outside was so chaotic that we were unable to reach our taxi back to the hotel, so what was then the Royal Ulster Constabulary, who had been happily watching on, stepped in, clearing a passage through the throng and ushering us into a police van for a trouble-free ride back to the hotel. Such are the perks of being the homecoming king.
But what impressed me was that throughout the mayhem, Nesbitt retained an unflappable affability. He also had a sharp awareness of the inherent absurdity of the situation. "I get an awful lot of people coming up and saying they went to school with me," he smiled knowingly. "There must have been 80,000 pupils at that school!"
In the intervening years, Nesbitt has not lost his ability to raise a quizzical eyebrow at the world. I have interviewed him many times since that mobbing in Portrush, and he has always maintained a capacity to send himself up. Most importantly, and in contrast to many more narcissistic members of his profession, Nesbitt possesses a rare sense of self-knowledge.
When we meet in a pub near his south-London home to discuss his latest drama, a compelling ITV1 conspiracy thriller called Midnight Man, he makes for cracking company. Leaping to his feet to act out stories, he is an inveterate socialiser with a genuine interest in other people; it's not all about him – he never fails to ask after my family.
His eyes twinkling beneath his receding dark hair, Nesbitt starts by regaling me with a characteristically self-mocking story about the limits of his own fame. "I was working this morning in central London and went for a quick coffee in Soho," he recalls. "This guy came up to me and said, 'Brian! How are you?' He had absolutely no idea who I was. A bit of me felt like protesting, 'Don't you know who I am?' But it was a good lesson. It's easy to get carried away with yourself."
Nesbitt has always been acutely aware of the dangers of getting carried away with yourself. Despite major hits with Cold Feet and, subsequently, Bloody Sunday, Murphy's Law, Jekyll and The Passion, the 43-year-old has avoided becoming intoxicated by his own success. Dressed in a stripy jumper that would not look out of place on the similarly mischievous Dennis the Menace, Nesbitt reckons that a jolt early in his career has helped him to keep things in perspective.
"When I did the film Hear My Voice a few years ago, I disappeared fully up my own backside for a while," he says. "Because I thought my career was taking off, I became a bit of an egomaniac and a pain in the neck. I thought I was God's gift to mankind and the greatest Irishman since George Best. As a result, I didn't work for a while and realised I had to change. I learnt that there are plenty of other actors who will do just as good a job as you. That was chastening.
"I also learnt the biggest danger is that you begin to believe the hype about yourself. Thank God that doesn't happen to me anymore. You can get too used to the pampered life – 'Can you draw breath for me because I'm too important to do it for myself?' I'm very lucky to have a mother and a wife who would kill me if I ever behaved like that. I never forget that I'm extremely fortunate. Sometimes I can't believe I do this for a living and have to pinch myself. It's not as if I'm going down a mine every morning, is it?"
Nesbitt is equally down-to-earth when assessing his professional image as "this charming man". "My mother certainly doesn't think I'm charming!" He is also ready to take the micky out of his reputation as a sex symbol. "I'm no pin-up," smiles Nesbitt, who for the past 15 years has been married to Sonia, an actress he met on a world tour of Hamlet in 1989, and who is the doting father of two daughters, Peggy and Mary. "Tragically, I get more letters from grannies than daughters. Quite often people come up to me and say 'my grandmother loves you'. An old lady approached me recently and asked, 'Can I touch you for luck?' That's my fan-base. But anyway, the very idea of being a heart-throb is ridiculous. You get to play a great character and people attach things to you that actually belong to the character. It's absurd."
Perhaps it is this acuity that has helped Nesbitt sustain his position at the top in the notoriously fickle world of TV. Five years after the end of Cold Feet, he remains a "green-light name", one of the very few actors in the industry capable of securing a commission merely on the strength of his moniker. Because of his stature, he was recently linked (erroneously, as it turned out) to the biggest role in television drama, Doctor Who.
He has certainly chosen his projects very cannily. The turning point came with Bloody Sunday, Paul Greengrass's landmark 2002 film about the Troubles in which Nesbitt played the civil rights activist and MP Ivan Cooper. "Nothing has had the impact that Bloody Sunday has had on me," he confirms. "In fact, Bloody Sunday the film might turn out to be a watershed for me, in the same way that Bloody Sunday in itself was a watershed for Irish politics. It was a defining moment. For years, acting was something I enjoyed, but it didn't feed my soul. But then I did Bloody Sunday ... It brings me out in tears quite often. It was a difficult process, but also an extraordinary process. It made me think for the very first time why I love acting. And why I love Ireland."
The role – which won Nesbitt Best Actor gongs at the British Independent Film Awards and the Stockholm Film Festival – steered him away from sunny "cheeky chappie" terrain into much darker realms. Such serious work as Wall of Silence, Passer By and Quite Ugly One Morning followed. He clearly relishes appearing in these dramas which resonate long after the closing credits.
"I was out Christmas shopping at the end of last year," Nesbitt recalls, "and this woman came chasing after me. She said, 'I work for a charity that gives refuge to prostitutes that have been trafficked here and I wanted to thank you. The last series of Murphy's Law [which dealt unflinchingly with the subject of sex trafficking] did so much for us. It showed people what is really happening.' A drama can't make the problem go away, but at least it can raise awareness."
Nesbitt also made a big impact last year in BBC1's Jekyll. He believes that Steven Moffat's six-part updating of the classic Robert Louis Stevenson yarn worked so well because, "so much of the story is timeless. Look at the idea of a split personality. Duality is unquestionably within us all." He bursts out laughing: "I know there is no shortage of Mr Hyde elements in me!
"We all have different masks we put on for different occasions. Everyone has got a dark side, and people often find it very seductive. As much as we all want to lead decent lives, we're all also attracted by the idea that something dark may lurk within us. The devil has all the best lines – that's why Jekyll is such a potent, universal myth. It was also great fun to play. You got the chance to do stuff you hadn't been allowed to do since you were a little boy and your mum told you to stop showing off!"
Nesbitt is now continuing in the same thought-provoking vein with Midnight Man. Scripted by David Kane, previously responsible for Sea of Souls and Rebus, this new three-part drama centres on Max Raban (played by Nesbitt). In this piece, which starts on ITV1 next month, Max is a formerly acclaimed journalist who is now falling apart at the seams. Devastated by the fact that he revealed a source who then committed suicide, Max is estranged from his wife and daughter. Living on his own in a flat that is as wrecked as his psyche, he is suffering from phengophobia, a fear of daylight.
His dream of becoming a fêted investigative journalist has been destroyed, and Max is now scraping a living by rummaging through famous people's bins in pursuit of scurrilous stories. But one night, he makes a chance discovery in a dustbin that reveals an international conspiracy, but also puts his own life in grave peril.
Nesbitt explains that there is dignity in Max's quest. "His vocation is to uncover the truth, and there's something noble in that. I've got much more faith in journalists exposing the truth than in politicians. As long as we have politicians, we'll need people to expose their lies. There will always be a place for investigative journalists."
The actor, who has himself fallen victim to red-top exposés in the past, goes on generously to praise journalists, a breed who generally vie with estate agents for the title of "most loathed job in the world". "It's easily forgotten that journalism can be an extraordinarily noble profession," Nesbitt argues. "We've been swayed the other way by the press's thirst for tittle-tattle. That has rebounded unfairly on journalists because there's something worthy about uncovering corruption. It releases great writing." With a knowing smile, Nesbitt adds: "I think the idea of me playing a journalist is quite funny. I can see the irony in it!"
Commendably, Nesbitt does not seek to blame the messenger for his indiscretions with a couple of women, which were front-page news in the red tops a few years ago. "The downside of fame is of your own making," he says, exhibiting a self-awareness not always present in erring stars. "Obviously, different publications have different ways of reporting stories and of garnering information, but they very rarely invent things. The papers can be intrusive, but they're only as intrusive as they're allowed to be. If I were to blame anyone for all that stuff, I'd blame myself, never the press."
Nesbitt originally intended to follow his father and three older sisters into teaching. Now he says that he cannot begin to envisage himself in that profession. "Imagine me at the age of 22 teaching 18-year-old girls French and discussing the Existentialists," he roars with laughter. "I'd have got into all sorts of trouble!"
So he abandoned a French degree at Belfast University in favour of studying acting at the Central School of Speech and Drama in London. He now feels that, "there was something in me that wanted to get away. There was always a claustrophobia about Ireland."
After eye-catching roles in Common as Muck, Jude, Welcome to Sarajevo, Touching Evil, Ballykissangel and Waking Ned, he had his breakthrough wearing a rose between his buttocks in the 1997 pilot episode of Cold Feet. Despite intense pressure from ITV, Nesbitt feels very happy that the series went out at the top in 2003, before fans could start shaking their heads and muttering, "it's not as good as it used to be".
Now he has a growing profile in the US. Matt Damon came up to him after the premiere of The Bourne Ultimatum and raved about Nesbitt's performance in Bloody Sunday. But we won't be seeing "Jimmy goes to Hollywood" headlines any time soon. "The idea of having to go to Hollywood and sit around waiting to be offered the part of a baddie with an accent I can't do simply does not appeal," he says. "Transporting my family to LA just to hawk myself around seems a hell of a lot to ask."
Besides, Nesbitt carries on, "I'm in such a privileged position here. There is such a vast array of talented directors in this country. So why would I want to go to the States and wait for something I might not be right for anyway?"
Staying here also allows Nesbitt more time to devote to charitable causes. A man who is passionate about his native land, he is a patron of Wave in Northern Ireland. "It's a charity set up in 1991 by women from both sides of the community who'd lost spouses in the Troubles," he explains. "Now they help to look after anyone who has been left bereaved by the Troubles.
"There are analogies with the South African Truth and Reconciliation Commission. People who have held in their grief for 30 years are now coming forward. You can't move on and build a future unless you address the problems of the past. You have to make sure that it doesn't happen again and that people never forget about it."
He continues: "the people affected by the Troubles have to be reintegrated into society. The two communities have been taught two different histories, but groups like Wave aim to bring them together. Dialogue is the key to the whole process. It's about embracing different cultures rather than constantly fighting about them."
Nesbitt is just as committed to his role as an ambassador for Unicef. He has been on trips to Zambia (to highlight HIV/Aids) and Sudan (to shine a light on the struggle of child soldiers). "What I like is the fact that there is no romanticism at Unicef," he comments. "It's very black and white. Their attitude is 'this is dire – what can we do about it?' We must never forget that children have a right to a life without fear, to clean water and to education. The whole of Sub-Saharan Africa is in extraordinary danger right now. HIV/Aids is wiping people out, and the West is not fully embracing what it needs to do to help. Will the next generation of African children survive?
"My role is to get across to the public the urgency of what needs to be done. I can see that some people would be cynical about it – 'Oh, he's only doing a charity gig to further his own career.' But if all else fails, at least I've put my profile to some good use."
Nesbitt must dash – he has to pick his daughters up from school. But before he goes, I take the opportunity to reflect on how far he has come in the past eight years. He is always busy – he has never lost his "Protestant work ethic", as he puts it – but now thinks his work is far more rewarding. He has also undergone trial by tabloid, but feels that those tribulations have only made him stronger. All in all, he says he couldn't be happier. "You know," he muses, "I've always been mouthy, always been one for the craic. But I've never been fulfilled. I've always felt a bit empty somewhere. Now I can finally say I'm proud of myself. Things like Midnight Man are a tremendous reminder of how wonderful the medium of television can be and of how lucky I am. I am paid handsomely to learn some words, deliver them in the right order and then find out where the wrap party is. Then I go home in my Mercedes to the wife and two daughters whom I love. My life is very blessed. And Manchester United won the title again last season. What more can a man want?"
There is a pause, before Nesbitt breaks into one final grin: "I know that every actor is replaceable. The more hair I lose, the more I think, 'God, I have been very jammy to get this far'."
'Midnight Man' starts on ITV1 on 8 May