5. Casting Unknown Leads

I always wanted someone real for Mia,” says Arnold. “I wanted someone who would give me trouble for real. I wanted a girl who would not have to act, could just be herself.”

The casting process took some time before Katie Jarvis was 'discovered' on a station platform. “Originally we went down the more traditional routes as Mia needed to have a passion for dancing,” explains Arnold.

“We saw girls from agencies and dance clubs. Then we started looking in Essex, in youth clubs, markets, shopping centres, anywhere teenage girls would hang out. Katie was found on Tilbury Town Station arguing with her boyfriend.

When she was approached she didn’t believe it was really for a film and wouldn’t hand over her number.

"She has a lot of spirit but also a vulnerability and innocence that felt right. She came from where we were going to film and felt very real.”

But when it came to show her hoofing skills at the audition, the actress was hesitant… “She had never done any acting or dancing before,” explains Arnold.

“She didn’t dance at all in fact, didn’t even like dancing. The first time I asked her to dance she was too shy and so we left the room and left the camera on so she could dance alone."

When I watched the tape back I saw that even though she was not a dancer in any way she was totally herself when she was dancing. There was no mask, no show.

"She was able to be herself totally even though she didn’t like doing it. I thought I would take the risk. I wasn’t sure if it was going to work, Katie had never done any acting but whatever happened I knew she would be herself and I wanted that the most.”

With Jarvis and Rebecca Griffith - who plays live-wire younger sister Tyler - both newcomers, Arnold knew she'd need strong supporting actors to help her young leads…

Next: ...And Making Sure They're Supported