She says the stage was a red herring; had Cambridge been running a film studies course while she was an undergraduate (reading social and political science), she would have found herself gravitating towards it. But it wasn't, and nor did she have much exposure to film as a child (the home of Major-General John Swinton, a lord lieutenant of Berwickshire in southern Scotland, not being a natural home of the avant-garde, one suspects) though she recalls that during the endless, lonely summer holidays she would go for long rides every day - and in her head, the cameras were rolling: "My horse used to cross over the cobbles from the courtyard into the drive, and at that moment I used to say, 'Action' and then I would be in a film."
What interests Swinton about performance, in life as in art, is the gap between what is projected and what is true. She recalls a train trip to school, when she was about 10: "I was pretty miserable, but I wasn't showing it. And I suddenly became aware that you can feel one thing and show another, you can fool people, you can never know what someone's thinking. What I realized then - this is pretty awful, but it's true, and it's good to get this digested early - is that you can't take sincerity for granted.
"There's this myth in drama, which I think comes from theater, and I think it comes from writers, who are too articulate for their own good, that everyone is sincere and able to communicate their ideas exactly at the moment that they are having their ideas. And it's not the way it is. And you can explore that in cinema. I tend to make friends with filmmakers who are interested in inarticulacy."
Jarman, who died in 1994, was a way into that, since he was a visual artist rather than a literary filmmaker. She misses him, and says there has been a decade of "cultural amnesia" about his kind of art. She's working with Isaac Julien on a new film about Jarman, to be released next year. What she misses, she has written, is "the whiff of the school play" about his work. "It tickles me still and I miss it terribly. The antidote it offers to the mirror ball of the marketable ... is meat and drink to so many of us looking for that dodgy wig, that moment of awkward zing, that loose corner where we might prize up the carpet and uncover the rich slates of something we might recognize as spirit."



