Hannah, I should therefore explain, plays Matthew, Simon Callow's lean, handsome boyfriend. As marital mayhem erupts around him, Matthew dispenses offhand pearls of wisdom in a gentle Scottish accent. 'It's not a headline- grabbing part,' says Hannah, 32. But later on, he has audiences blubbing and critics raving over his eulogy and reading of W H Auden's poem 'Funeral Blues'. As if the film hadn't raked in enough money already, this poem and nine more by Auden have recently been compiled as an audio- book entitled Tell Me The Truth About Love. The poems are all recited by Hannah. But the face on the cassette's cover has a floppy fringe. This must be galling.
'No, not at all,' says Hannah, in a manner as relaxed and self- effacing as Matthew's. 'I thought Hugh was fantastic in the film. I was watching him while we filmed it and he was doing this big comedy acting like I hadn't seen for a long time. I thought he was really being brave; it could have worked against him. But he obviously knew what he was doing. When I saw the premiere I was just swept along with it. I think the first time I noticed myself was in the funeral scene. Then I went to the toilet.'
Hannah is Hugh Grant in reverse. Grant is the Oxford toff; Hannah, the casually dressed common man. For Grant, acting is a high road to the high life; for Hannah, it is a job he takes seriously. Grant admits that he is happiest when talking about himself; Hannah strolls into the pub in which we meet and immediately asks me how things are going at the Independent and which part of Scotland I come from. Grant loves to be noticed in the street; Hannah isn't bothered. 'If you're going to be recognised, it's nice if people recognise you for a good thing,' he shrugs. 'You're not the guy who chopped the heads off 14 women in Yorkshire; you're the guy in that film. It's good if your work is enjoyed.' He appears unaffected by Four Weddings' success, probably because showbiz glitz was never something that attracted him in the first place. When he moved from East Kilbride to Cumbernauld - 'from one shit-hole to another' - at the age of 16, he was leaving home to become an apprentice electrician. Soon he was desperate to try something 'completely different'. He opted for Glasgow's Royal Scottish Academy of Music and Drama, because it didn't require entrance qualifications. It was the first time he had ever acted.
After the RSAMD came a variety of TV and theatre roles and the inevitable bill-paying jobs, such as a Volkswagen advert two years ago. 'The only way I could get through it was by pretending I was one of those people on Tomorrow's World. It was pretty cool: I was just lucky I didn't have to have my head turn into a giraffe or to make funny faces, running out of the bedroom with Coco Pops up my jumper or something.'
On Tuesday he brings dignity to the partof a transsexual murderer in the Carlton television play Joan. After seeing this role and that of a gay character in Four Weddings, the sexuality question springs to mind.
'Yeah,' he says.
So here it is.
'What is the question?'
Are you gay?
'Em . . . I think . . . Nobody berates anybody for playing heterosexuals all the time. If it's a good character and a good script then do it. I've done about four gay roles out of all of them.'
Is that a no, then?
'I don't know . . . Is it politically incorrect to make a statement about it?'
I'm not sure. Just interested.
'As it happens, I'm not gay. But I'd hate you to write 'John Hannah - Not Gay' at the top of the page, because then it becomes an issue, which it's not.' He lives in London with his girlfriend and two cats.
In September he stars with Michael Gambon in Faith, a two-part 'political-intrigue-and-growing-up real-life-sort-of-drama', as a journalist investigating a 'Matrix Churchill kind of case'. 'It's right up my street politically,' he says. In the mid-Eighties he was involved in the Workers' Theatre Movement, a left-wing company set up by some friends, including Anna Chancellor, 'Duckface' in Four Weddings. He has also been in a party political broadcast for the Labour Party. 'It was no different from selling a Volkswagen,' he says. 'You just have to look reassuring.'
Now his work is not overtly campaigning, but he is still incensed by the way 'political stagnation' has affected the arts. 'Thatcher strangled thought and ideas and creativity at birth. The only thought people had during the Eighties was to make money. Directors want to make a career for themselves, so they go and do a big Shakespeare play, something that gets them noticed. It's a self-advancement thing and it's there right across the board.
'There are no new ideas anywhere at the moment. It's the same in football. I don't think it's coincidental that none of the British teams qualified for the World Cup. The only person in the English league with any flair at the moment is a Frenchman.'
'Joan' is at11.10pm Tues, ITV. 'Faith' is at 9pm 7 & 8 Sept, ITV. 'Tell Me the Truth about Love': see W H Auden competition, below.