Scot of the Year: TILDA SWINTON. Chosen by film-maker Mark Cousins

By MARK COUSINS

Mark Cousins was Tilda Swinton's co-organiser for the most talked-about film festival of the year, the Nairn-based Ballerina Ballroom Cinema Of DreamsTILDA Swinton doesn't read about herself so I can exclusively reveal, without her knowing, that she is totally two-faced and a nine-out-of-10 on the diva scale. Everything is "me, me, me". Her leg-polisher travels everywhere with her. She's only interested in herself, which explains her total lack of taste. She knows hee-haw about style, and couldn't say anything funny if her life depended on it. And vain? Don't talk to me about vain.

These are fun sentences to write because they are preposterously untrue. As I've run film festivals and had a TV talk show, boy, I've known divas in my time - and mirror moochers, and dour, soor plooms - and the divine Ms S, with whom I've worked for much of this year, is as far away from them as you can get. Much as it pains me to say it, because it's funnier to take the piss, Tilda Swinton is a copper-bottomed, triple-distilled mensch.

That's why she's a Scot of the year; like Geraldine the social worker in Glasvegas's brilliant song on their first album; or like the Asian guy with a strong Leith accent who opens the wee shop on my street at seven every morning and is still there at 10 at night, and from whom I buy my paper every day and whose very existence makes me happy. If Tilda wasn't first and foremost a great human being, a mensch, I wouldn't be writing this. I wouldn't be proposing her as Scot of the Year.

But she is, and so I am. When she and I were doing the Ballerina Ballroom Cinema Of Dreams film festival in Nairn in August, this woman - who comes from a military family and whose most famous collaborator, the filmmaker Derek Jarman, did too - mentioned several times the spirit of the blitz. She meant that we were all in it together. The film tickets were cheap and people got in free if they baked buns. Old Nairn ladies rubbed shoulders with chic young Germans, London trendies and loads of local kids. Surveying this mix, I think I saw something like rapture in Tilda's eyes. Class, age and sex differences were oot the windae. We all mucked in. Tilda is a mucker-inner.

That's my starting point. Then, only then, can I talk about the new big thing that everyone knows about her: the big O, the Oscar she won for her role in the film Michael Clayton. It's best described as a fairytale. Imagine a skinny, Egon Schiele drawing of a woman leaping from the page. Imagine her taking a tardis to LA, or driving there in an ice-cream van. Imagine that by some weird zap of a sonic screwdriver she finds herself a spy in that bauble called Hollywood. Imagine that, inconceivably, Hollywood doesn't quite notice her badges of difference and, so, asks her to star opposite its current Knight Errants, George C and Brad P, both of whom are more interesting than it. Imagine that the casting works, and the Schiele drawing gets invited to an amphitheatre called the Oscars. And, without the slightest sign of caprice, she shows up looking as if she's wearing no make-up (at the Oscars!), looking like something that Tim Burton drew. At the silly thumbs-up/thumbs-down moment, the "and the Oscar goes to" moment, with the crowd on the edge of its seat, she gets the thumbs-up.

So Tilda Swinton is mensch + fairytale. What else? She's a dude because of the way she reacted to the fairytale. She gave away her Oscar (so I hear) and hasn't watched her acceptance speech on YouTube. Beyond this breathtaking insolence, this totally intelligent understanding that seeing yourself makes you self-conscious, the next thing that strikes me is her writing. I started working with her because I read a letter she wrote to her son Xavier about cinema, which glinted like a shoal of fish and which was published around the world. Her use of words was so lively. It reminds me of my granny, who once said that a friend of hers hung onto her man "like a bucket of skins". Language hangs on to Tilda like a bucket of skins. She and I co-wrote an introduction to a film book recently. She penned hers in snatched moments in airports, yet it made me cry.

At the end of her life, the great silent movie star Lilian Gish was asked what is the most important thing in life and she said one word - curiosity. Tilda is into everything. I told her recently that a great charity, the International Medical Corps, wanted to take two of the films we presented at the Ballerina and show them in Somalian refugee camps in Ethiopia, and she texted back: "Can we go?" She and I are recreating a forest in Nairn, in Beijing, digitally. She wants to drive to Tehran. This dogged, centrifugal internationalism is, surely, Scotland at its very best.

But Tilda is also committed to Scotland a la folie, and in a range of ways. Nairn is all that public school in England wasn't: human and friendly, a place to live a real life. She paid for the Ballerina Ballroom there out of her own pocket. She is patron of the Screen Academy Scotland, the Edinburgh Film Festival, and Filmhouse's friends scheme, to mention just the things I know about. And on a drive to Forres recently she talked about Scottish trees in such a passionate way that our Beijing forest is the result.

And there's more. What other performer, since Julie Christie in the 1960s, has chosen films by director rather than script, thus committing to cinema as a visual rather than literary medium? Tilda loves imagery. In Scotland of all places, where the legacy of John Knox seems to mean that words are respected more than images (the latter being redolent of surface and fashion), this is brassily modern. And her reaction to the media coverage of her private life was modern in a different way. That she has a sweetheart but lives happily with her kids' dad, John Byrne, wrongfooted the newspapers. They were belatedly agog at what they wrongly saw as a ménage a trois. Tilda didn't let this get to her. It didn't dent her optimism or steal her thunder.

What else? A few weeks ago, Tilda and I had an important 8am meeting in Claridges in London. We were both up until 4am. I arrived at the meeting with a face like a Halloween cake. Tilda showed up, after four hours sleep, looking fresh-faced and entirely beautiful. How does this work? Answers on a postcard. In the Ballerina Ballroom, we tightened our makeshift, sheet-like movie screen with ugly clamps. I was trying to hide them but she said, "no, leave them visible" and added later that "ramshackle rocks".

I have learnt from Tilda that ramshackle rocks. I think I knew this, but her saying it made it clear. Her significance for Scotland lies in the aesthetic boldness of such insights. The world thinks of Scotland as whisky, golf, Burns and Sean. Fab. But how good for us that we have this fairytale mensch, this iconographic Schiele timelord? Tilda's intellect and energy, her modernity and humanity, are brilliant adverts for 21st century Scotland. John Stuart Mill said that we should live "a life of exertion", and boy, does she.

Luckily, to stave off total hagiography, there are bad things to say about Tilda Swinton. Her car is the messiest I've ever seen and she laughs very weirdly at Father Ted.

I identify with no flag, but I can say that people like Geraldine, my local shopkeeper and Tilda make me proud to be Scottish. They are the real deal. Tilda Swinton is the doughnut, not the hole.