James Nesbitt discusses his latest role, as the Commissioner of London's police force in Babylon...

You play Commissioner Richard Miller in Babylon. What attracted you to the role?

Well, obviously a big part of that was Danny Boyle. I worked with him years ago on a film, Millions, and I remembered what a complete delight he is to work with. He's incredibly collaborative, has this extraordinary energy. He expects everybody to have the same kind of commitment he does, but he does it in this unique way. He's really egalitarian, he treats everybody in the same way, and he's also got incredible vision and humour and sensitivity. That was very appealing.

Sam Bain and Jesse Armstrong were also big draws - I'm a big fan of Peep Show and I love Fresh Meat. I got the script, and I loved it - I thought the writing was so original, so funny. Although, even though it's being billed as a comedy drama, I don't think of it like that - I felt it was really honest and dramatic, even though there's clearly comedy in it.

I thought it was really interesting to play a character with such authority. He's very progressive in his ideas, he probably has a history of being in the police force in Northern Ireland, so would have seen the worst of the troubles as a young policeman, and maybe been instrumental in bringing about the peace. And the further we got into it, there was the whole complexity of what it must be like to be the senior police officer in the land. To serve the millions of people in London. And one of our locations, Richard's office, looks out all over London, and it just gives you an indication of how epic and how vast and how pressurised that situation is.

You've played policemen before. Now you're playing the top police job in the country, does it feel like a promotion?

Well, it doesn't get much higher than that! I played Murphy for years, who was an undercover cop. What's interesting about that is, as an undercover cop, you're not responsible for a load of other people, you're only responsible for those around you on the case that you're working on. Richard has to look after the welfare of 10 million people, so although it felt like a promotion, I think the complexities of what it must be like to be the Commissioner, the politics involved, the endless to-ing and fro-ing with Westminster and the press, I think it's a hugely pressurised job. John Stevens, who resigned, was the first Commissioner to resign since the one in Jack the Ripper's time. It's a very protected job, it's a very important job.

What research did you do for the part?

There are different strands to the drama, and every different group in the drama had a different police expert involved with them. We were very lucky because we had Brian Paddick come and talk to us for quite a long time, and he gave us a very interesting insight into just how complicated and how fragile that world is, in terms of keeping everything together, keeping clear of scandal, keeping the politicians happy, serving to community and so on. He was great. I also read quite a bit. And the script brings you a lot as well.

Knowing what you do now, what sort of a policeman would you have made, and what sort of a Chief of Police would you have made?

Oh God! I like to think that I'd have been quite community-based and quite progressive. But in terms of Commissioner, I think I'd be out on my arse within about a week. I'd definitely upset someone.

What was it like working with Danny and with Sam and Jesse?

Well, like I say, I'd worked with Danny before and he's brilliant. He's the most collaborative, least ego-driven director. He reminds me of Paul Greengrass, actually. He's just got this amazing energy, wonderful vision, always listens to his actors, is very funny, great with the crew. And Sam and Jesse are just a delight. They're very funny and very accessible, very switched on, incredibly intelligent. It was such a great atmosphere, I can't wait to get back there and get working on it all again.

People who are familiar with Peep Show and Fresh Meat will be expecting a knockabout comedy, but it's a bit more complicated than that.

Yeah. Certainly there's comedy in it, because that's the way they write. But I don't think it's knockabout. They picked different strands of the police, different departments, and they found that some areas are more ripe for comedy than others, and some characters are funnier than others. And there's a serious edge to it, because it's a serious business. I'd describe it as 'a drama that is funny'.

It's got a fantastic cast. Is it exciting to be working on a show with such a strong line-up?

Oh it's wonderful. And it's so ensemble as well. Brit Marling, who I do a lot of my scenes with, was great. Bertie Carvel, who I didn't know before, was just wonderful. I think Danny and Gail [Stevens, the Casting Director] deserve a lot of credit for that. Then again, if you're Danny Boyle and you're doing your first TV project for 20 years, and you've got Sam and Jesse writing it, there's every chance you can name whatever cast you bloody want for it.

Are there any roles you still yearn to play, or people you long to work with?

I'd love to work with Paul Greengrass again. There are loads of roles I'd like. I think I'm entering a different phase as an actor. I'm looking forward to getting older, and the parts being a bit quirky and interesting. I just want to be challenged by new writing, and hope that people still want to employ me.

What roles in your career have given you the most pleasure?

It's hard to be specific. Clearly the jobs that had an impact were things like Cold Feet, which introduced me to a very wide audience. Clearly there were good things that came out of that, in that it opened the door to other work, and there were different things in that it made me very famous, which can be difficult at times. I loved that, and I loved how that character developed. The work we did on Murphy's Law was great, we really changed it and made it very gritty. That was a very good cop show. And Bloody Sunday was hugely important to me, in terms of allowing me to see that acting could have worth. I always thought it was a rather silly profession, but this showed me that something like a TV drama can make a real difference to people.

Do you watch much TV yourself? What have you seen lately that you enjoyed?

I watch things like Match of the Day and horseracing. In terms of drama, I love watching Stephen Dillane in The Tunnel. I'm not generally a fan of remakes, but Stephen Dillane I worked with years ago on Welcome to Sarajevo, so I gave this a go, and I was just captivated by him, I thought he was brilliant.

Babylon is on Channel 4 on Sunday 9th February at 9pm.