He’s turned the screen Scarlett after a long and alien journey

Johansson has also been orbiting the project for a long time. She read a first draft of the script several years ago. Although interested, nothing came of it until Glazer pared down the story and re-wrote the script. Then came the moment of epiphany. “For quite a while, I hadn’t decided 100 per cent that she’d be in the film and she hadn’t decided whether she wanted to be in it. When the final script was ready, I sent it to her and that’s when the conversation became serious. There was one phone call in which it became obvious that we were going to do the film together. It was as if she and I had just read the same book and we were both talking really enthusiastically about it.”

It was a brave decision by Johansson for this is no Hollywood star vehicle. She has very little dialogue, many of the scenes are improvised and involve people who do not even realise they are being filmed. There are also nude scenes. “I told her all the things it would involve because I had to be sure that she’d be up for that before we started shooting it.

“There’s a long history of great American film stars coming to England and working with directors who are not necessarily making films in the same way that they would be in the States. Some really great performances and films have come from that intersection between the Hollywood star and a very left-field story and sensibility.”

Much of the film takes place in the white van which Johansson’s character, disguised in a black wig, uses to hunt down victims. Glazer decided that it would be a good idea to do some of the scenes for real. So with hidden cameras in the dashboard, the actress would stop the van to ask Glaswegians if they would like a lift. Some of these encounters made the final cut. “I was sitting in the back of the van with the cameraman, two or three other people and all the sound and recording equipment while she was driving us around. She is like a lion in the Serengeti looking at the wildebeest, waiting for the stragglers.” We are not told why she is hunting or indeed anything about her mission. Glazer thinks this is important. “You want her to remain inscrutable. We wanted her to be as much of a mystery at the end of the film as she was at the start. But what we recognise in her is what she has learnt of us. She begins to believe what she is looking at in the mirror is who she actually is.”

Glazer is fairly sure that his creativity was not something that was encouraged during his days at JFS in Camden. However, he does credit the school with his “love affair” with Israel, which was sparked by his participation in the Givat Washington scheme in which small groups of pupils spent five months in an Israeli religious boarding school. So did he chat to Johansson about Jewish stuff? “Her mother is Jewish, her dad isn’t. We spoke a little about that. She’s very proud of her Jewishness and I guess we connected on that level.”

After JFS, Glazer went to art school because drawing was, he says, the only thing he was good at. He did not have a burning desire to be a director until he started to shoot music videos for friends’ bands. “Everything I know I more or less taught myself. My first job was making film trailers. I’d be sitting in a room with all this footage trying to understand how things cut together depending on the context. That was a big part of my education.”

He still makes ads and music videos — he filmed several during the time Under the Skin was in gestation — but feels a little disillusioned with the advertising industry, believing fear is stifling creativity. Whether in advertising or in movies, he has to identify strongly with what he is doing. “I’m not the kind of director who has 10 projects on the go to see which one works out. It feels more like music to me — I have this idea for an album and I want to make it. If I do something, I have to do it well and sometimes that takes a little time.”