Your new series is Ackley Bridge. Explain a bit about the show.

The basic premise is that it starts on the first day of the merger between two schools in a fictional Yorkshire town called Ackley Bridge. It’s a merger of a school that’s become completely white with a school that’s become completely Asian. That’s very much the case in the North, and I think all over the country – schools have become very, very segregated. So this is an attempt at bringing people together to see if they can get on. It’s a very optimistic view, so although the series does deal with some tough issues to do with sexuality and violent parents and addiction, which makes it sound rather grim, the spirit of it is very positive and optimistic and warm and funny.

Why did you want to take it on?

I’ve never done a drama series before, and I’ve never wanted to, and I’ve done single dramas and documentaries that tend to be shown way after the watershed. But this was something that George Faber, from [production company] The Forge, sent to me, because he thought it might be my sort of thing. And I said to him that I didn’t do series, and the next morning I received an early version of episode one and I thought “I have to do it, it’s got everything that interests me about race and class and so on.” And also it felt like an opportunity to have almost 50 per cent Muslim characters, and not a single one of them is a terrorist. I guess that was the big inducement to me. I was speaking to the actors who came up for the parts, and all of the men said that the only thing they ever get offered is extreme fundamentalists about to embark on violent acts. And that simply isn’t true, and I think it’s causing a lot of problems. So doing something that shows that Muslims are just people seemed great – if there was ever a time where we needed to do that, this is it.

Do you go off and do your own research, or is it all there in the script for you?

It’s a mixture – the scripts were at a fairly early stage, so I was allowed to have quite a lot of input, which was great. One of the fantastic things about being the lead director is that you get to choose the locations, you get to cast it, and you get to establish a way of working. I think it’s so important not to just parachute into a community and tell people to shut up on their own streets, do your own thing and vanish. All of the supporting artists in the school come from local schools, and there are about eight speaking parts played by kids who we found by holding a lot of auditions. We did street castings, went to boxing clubs and youth clubs and schools and playgrounds, and literally sometimes met people in the street and asked them to come in for an audition. I think it’s the right way to work, it’s an ethos that I really believe in, so the community feels it has something invested in the show. But also, I think it gives it a feeling of authenticity that you wouldn’t get if you were shipping in a whole lot of kids from drama school. And by going into the community and speaking to people on the ground, you learn a lot more about the world you’re trying to portray.

Did anything in your research surprise you?

I think we’re always surprised. Even though I’d spent a long time in Leeds with the Pakistani community, and I’d stayed in touch with two or three people, it’s funny how insidious this representation of other people is, even when you know from your own experience that it’s not true. Gradually, you start to think that people are different from you, and then you meet them and you realise it’s not like that. I was struck by how there’s so much more in common we have as human beings than the things that divide us. Every time I have an opportunity to be in another world, that’s the thing that delights me and surprises me all over again. Of course there are cultural differences – girls are much more monitored, can have much less freedom in the Muslim community – but there is so much more that unites us. At the wrap party, which sadly I missed as I was working, Zain, one of the boys who has a small part, he stood up and said “Before this, I didn’t really know any white people. Now I have a lot of white friends.” It can work. People can actually get on.

Why did you decide to film in Halifax?

Halifax had already been decided upon. With this premise of merging school, they looked for an empty school that was still in relatively good condition that could be used as a base, and what used to be St Catherine’s school in Halifax was the one that had all the elements to make it work. So I’d never been to Halifax before. But I think it’s so important for us to get out of places like London, so you realise the world doesn’t revolve around people in London. The Brexit vote that surprised so many people didn’t surprise me. I don’t spend all my time with middle class people in London. Life outside is different. I think it’s so important to have dramas that reflect the fact that most people live in provincial towns far away from the metropolis.

What was it like shooting there?

Well, it’s a beautiful place. It’s an old mill town, which is why the Pakistani community is in that area, because that’s where the cotton trade was. But obviously the mills are now office buildings and luxury flats. But you’ve got this beautiful architecture, and it’s in the middle of the Pennines, so everywhere you look, there’s mountains emerging out of the city.

But there are some estates there too, which you filmed on. How was that, and how did the locals find it?

There have been periods when I’ve filmed things, like Tina Goes Shopping, when people on the estate were very suspicious and thought I was working for the police, and wouldn’t speak to me. But that didn’t happen in Halifax, everyone was very welcoming. We didn’t have any aggro whatsoever, it was remarkable. I think it’s partly because we did the groundwork, we didn’t just show up. We went round and spoke to people and explained what was going on. And we’d get local people involved – for example, the street that Missy and Nas live on, a lot of the extras are the people who live on that street. That really changes how people feel about filming.

You’ve had such a varied TV career. Why have you moved between genres so often, rather than sticking with one?

For me, it’s all about the story, and there are certain things that really interest me, like marginalised people. When I was a little girl, growing up in the British community in Uruguay, at carnival time people came into town from the poorer areas, and went drumming in the street. I was desperate to join in, and much more curious about their lives than the rather oppressed community I lived in. So I think my obsessions have remained rather the same all the way through. And it depends on the story – what is the best way of telling that particular story?

So the story comes first, and the medium comes afterwards?

Yeah. I would say that’s probably the case. But then I also get offered things. If somebody had offered me some high end period drama that I felt I wouldn’t be able to bring anything to, I wouldn’t do it, because there are people who could do that much better than me, and it doesn’t really interest me. But I don’t get offered lots of different things, and mostly I generate my own work. In this case, it was just something that came along that I realised I really wanted to do. The idea of doing something for hopefully a large audience, that has real humanity at its centre, and has a large Muslim cast, was irresistible.