Under the Skin draws Jonathan Glazer back to Glasgow

We are in a Glasgow hotel talking about his new film Under the Skin and the conversation has a lot to do with the real and the unreal, perception and disguise.

Adapted from the 2000 novel by Michel Faber, and chosen for the closing gala at the Glasgow Film Festival last Sunday, Under the Skin stars Scarlett Johansson as an alien who cruises the streets of Glasgow in a van, picking up men for her own, let us say unusual, purposes.

To give viewers the sense that they were witnessing the real world through unearthly eyes, the 48-year-old British director used hidden cameras to follow Johansson's character as she moved through the likes of Buchanan Galleries shopping centre and along the city streets.

"We had cameras hidden in everything from a cameraman's sleeve to a 'wet floor' sign," says Glazer. "We worked out where we wanted the cameras to be as you would conventionally, and then worked out what the 'hides' for those cameras could be. So that for you or I on our Sunday morning shopping expedition we wouldn't be aware."

After filming Johansson asking directions of strangers and trying to lure them into the van, the crew would seek permission from the unsuspecting locals to use the footage.

"It felt a kind of Jeremy Beadle sort of thing," says Glazer of this jumping out the van act. "Some weren't keen on the idea of giving their permission to be used and others were fine about it. We were lucky enough that we got enough strong scenes with people who had been filmed unsuspectingly and they were okay for us to proceed."

The result is a film unlike any to come out of Scotland before, and one that is set to stir debate among the many admirers of the book. Glazer counts himself firmly among the latter, but as it turns out he has never met Faber, who lives in Scotland.

"The book was very much a kind of jumping off point for me, I kind of understood fairly early on that it wasn't a direct adaptation that I was interested in." There are significant differences between the novel and the film. Key among them is that the hitchhiking scenes take place in Glasgow rather than on the A9.

For Glazer, who also wrote the screenplay, this was all part of the process of taking the book from page to screen. Earlier drafts had scenes in Edinburgh as well, but it soon became clear to Glazer that the film had found a home of sorts in Glasgow. "It just felt like the right environment," he says.

Glazer had worked in the Glasgow before, memorably exploding 70,000 litres of paint over disused tower blocks for an advertisement to sell Sony Bravia televisions. This is Glazer's other career, as a director of commercials and music videos. In this guise, he has been behind the likes of the famous Guinness ad with white horses riding the waves alongside surfers, Jamiroquai's Virtual Insanity video, Massive Attack's Live With Me and many another productions.

Having studied theatre design before going on to make trailers for videos, the ads and music videos were his film school and a way to pay the bills between his feature films, which began with the acclaimed Sexy Beast in 2000 (Ben Kingsley and Ray Winstone as sarf Lahndon gangsters), then the less well received Birth in 2004 (starring Nicole Kidman), and now Under the Skin. "I'm not exactly prolific," he says with a smile.

In making Under the Skin, Glazer had help from Creative Scotland, the BFI and Film 4. Even though the budget was relatively tiny, it was still a struggle to raise the rest of the money to make the film he wanted. That tussle became infinitely easier once Johansson signed on.

Glazer and Johansson had spoken about the project several times down the years. "It turned her head I think. She was very interested in the idea of it all and being in it." It was like talking to a friend about a book you both loved, he says. Johansson, who has directed her own short film and is about to make her directorial debut with Summer Crossing, based on the Capote novel, was intrigued by how Glazer intended to shoot Under the Skin.

"I went into this project with absolutely no idea how we were going to shoot it or what it was going to be," says Johansson. "I can't say I know what a normal film is. Nothing ever feels normal, even if you're making some huge action film for a studio. But this one was certainly an experience I'd never really had before, partly because there was the covert side of it."

With a film crew in the back of the van there was no risk to the A-lister in her drives through the dark and rain-battered streets. Glazer was more concerned about whether the concept of covert filming would produce anything. Either that, or The Lost in Translation and Avengers star, though wearing a brunette wig, would be rumbled.

"There were a couple of people along the way who clocked who she was but I wouldn't say it was hairy," he says. "Every day is hairy when you are making a film like this because you can really end up with nothing at the end of the day. But then when you do get it, it shimmers."

Fans of the novel will doubtless have their opinion on the film, as will the people of Glasgow. Although the movie was very warmly received at its Glasgow Film Festival premiere, one audience member at the Q&A afterwards complained that the city had been shown in a negative light. Glazer, for his part, said he arrived with no preconceptions, and wanted to show life as an alien visitor might see it.

He does not regard Under the Skin as a Scottish film, or indeed a film linked to any particular place. "If it was made in Potters Bar or the Hertfordshire borders it wouldn't be a parochial film to that." What he was after, he says, was a feeling of reality. "I hope it feels like it is. Certainly one side of how it is. I can't claim to have somehow shown Scotland because we haven't. But I do think we've rooted this story to where it is set."

That can be seen most convincingly in a scene where Johansson's character is walking along the Trongate and trips. Sprawled on the pavement, she is besieged with offers of help from passers-by, none of whom knew the cameras were rolling or who she was. She is lucky to get away without being adopted.

"I was certain that there were going to be people who would pick her up," says Glazer. "I thought that was a really exciting moment, a very simple demonstration of human kindness. But it couldn't be staged, it needed to be real. I wanted to put her in a street that was busy enough that it could happen, and it did - she was picked up every time."

Under the Skin opens on March 14