Had you had much experience of the Church of England before working on Rev?
Only as a child. My parents were good friends with our parish priest in Old Marston, Oxford. I think there's an archbishop of York in the 19th century on my mother's side - who were moderately churchy. My father was ethnically Jewish but his family converted to Catholicism.
How did the idea for the show form?
I'm afraid it started as an acting challenge - I played a vicar before [Mr Collins in Pride and Prejudice] and that worked, and then I heard about church schools and wondered what it was like to be a vicar, surrounded by people who were clearly lying. I'd also recently hit 40 - and a lot of people hit 40 and realise the way they've been living in their twenties and thirties isn't sustainable. All the stars were in alignment and the more we talked to vicars, the more interesting it became. There's not many things you can't look at through the viewfinder of the Anglican Church.
Were you surprised by what you found?
The fact that many vicars have periods of agnosticism was a big surprise. In the periods of my life when I've had least contact with the Church, I've always assumed a belief in God is a solid thing, but clearly it's a relationship; it has good days and bad days. For me, faith is more about aspiration than complacency - the smug satisfaction that other people find distasteful.
And that charge of smug certainty is now levelled at atheists.
There's an egotism at work in atheism: putting yourself at the centre of things. Intellectually, it's so easy to disprove the existence of God - a five-year-old could do it - so it's far more compelling, for me, to think there might be one. And far more beautiful to think that the known universe is an act of love. There is a machismo to strident atheism that I find irritating in adults. They sound like teenagers who've just worked out their parents aren't perfect.
Do you feel a responsibility to the Church?
For Rev, I applied acting principles to the subject matter; that it should be truthful to life and compassionate. That's a very highfalutin way of putting it; acting is also just showing off for money and wearing funny clothes.
Do you feel that vicars are in an impossible position? No one wants a "trendy vicar".
That's definitely a stereotype that makes people feel uncomfortable - someone who's put on a baseball cap to mask his essential unworldliness. But you do want your vicar to be sufficiently "in the world" to understand what everyone's preoccupations are; it's hurting the Catholic Church that they are not.
Does religion affect your political feelings?
I was sufficiently Christian by the time of 9/11 that when I saw George Bush and that face of incomprehension and stupidity broadcast all over the world, I thought: there's a moment here when a huge decision is going to be taken, and is anyone saying "turn the other cheek"? Yes, 3,000 people were killed in those towers and it was appalling, but how many more people were killed in Iraq and Afghanistan who don't have a cinematic epitaph - they just died at the side of the road, covered in dust, like a dog. Killed by someone who was operating, essentially, a PlayStation from the Pentagon.
Do you consider yourself a political person?
Not really. It's just that it's a New Statesman interview, so I'm giving it my best.
Do you vote?
Yes. I exercise my democratic right and feel grateful I'm not in a dictatorship but I don't really feel [politicians] are in charge any more, or that they particularly know what they're doing.
You were at Cambridge with Nick Clegg. Would you have gone if tuition fees were £9,000?
I was a complete chancer, academically. The fact I was there was wonderful, and the fact it was paid for by the state was extraordinary. Now it seems unfair. Sometimes I go, "Crikey! My contemporary is Deputy Prime Minister, and what should I have achieved? My bedroom is still messy and I haven't had any children."
What is it like, being recognised in the street?
People behave differently to TV stars and film stars; it's to do with the scale of the medium. Film stars get hushed awe, TV stars get slapped on the back. Neither is good for you. Famous people don't hear the word "no" enough.
What's your local church like?
They've stopped having music, presumably because there's no one to play it; they've got no heating. There's a sign on the door that says: "In the winter months, services will take place in the library." They're having a hard time.Even as an atheist, I find that sad. If you're in the mood for the melancholy of the decline of Old England, the Church is as good an index as any, I suppose.
Are we all doomed?
My answer to that depends on whether I've had enough sugar, or enough sleep.
1967 Born in Bristol and raised in Oxford. Went to the Dragon School, then Abingdon
1981 Is awarded the lead role in the BBC dramatisation of John Diamond aged 14
1985 Enters Cambridge to read English. Appears in Cyrano de Bergerac with Nick Clegg, directed by Sam Mendes, in 1988
2009 Takes the lead in the film In the Loop
2010 First series of Rev, which he co-creates with James Wood, is shown on BBC2
2011 Rev is recommissioned