Amy Beth Hayes spent a lot of time hanging out in McDonald's preparing for her role as a police sergeant in Sirens. She says: "Her accent, that's the key to Maxine. Once I'd found her voice I'd got her. There is something specific about the Leeds sound which I wanted to get across. I found it really important to her character. So I went up to Leeds a week before I started filming and sat in McDonald's listening to the kids and their mothers talking. It's a really good place to listen to accents because you do tend to get a wide range of people in there."

Amy also had help in the form of a woman police officer who helped with her research. "She was really helpful so on top of all the basic questions like 'are you allowed to wear nail varnish?' and 'how often do you polish your boots?', I was able to ask more personal questions. She kept underlining to me that being in the police is not a job, it is a complete way of life. And it is incredibly hard to forge a relationship with a civilian. She really informed my portrayal of Maxine."

Talking about her character, Amy explains: "Maxine is a sergeant at 27 and has obviously worked hard to get to that position so young. When you first meet her you might think she's a tad aggressive or has a hard exterior but that really is masking deeper vulnerability and a genuine sensitivity. She has to put up a barrier in order to survive in a man's world."

"Maxine and Stuart are best mates and the reason they have this bond is because they're very similar. Both of them see themselves as social misfits, they feel slightly separated from other people, slightly on the periphery. They're both trying to grapple with the world, understand people and relationships. They don't really get the opposite sex. Stuart has a problem with intimacy that he talks about a lot with Maxine. Maxine can't really allow herself to get close to a man because that could make her vulnerable. She doesn't allow herself to do that. So they find solace in one another's company because of that."

"But her relationship with Stuart is very frustrating for Maxine and she really struggles to understand what they are to each other. The will-they, won't-they element is always prevalent but it feels like as soon as they take a step forward they take a bigger step back. Then during the series Maxine meets Craig, a fireman who really unlocks her feminine side. That was lovely for me to play; going from being a woman with a hard veneer to someone who can actually melt in this guy's arms. It was a beautiful contrast."

Wearing the police uniform had a profound affect on Amy. "When you put the uniform on it is so heavy, even things like getting up from a chair have to be done differently. You can't cross your legs or bend forward because of the padded stab vest; it's like wearing a heavy corset. And the belt with handcuffs, CS spray and everything else on it is constantly getting caught on chairs and doors. Your relationship with space completely changes. It's almost impossible to be a woman in it. It was interesting for me as I haven't ever played a tom boy; I've always played women who veer on the more glamorous side. It was lovely not to have early make up calls; they'd just slap a bit of base on me, scrape my hair back in a pony tail and I'd be ready to go. Makes you less vain in a way, not worrying what you look like all the time."

One thing Amy did have to worry about on set was laughing... "It's been really fun to work with the boys. We're all the same sort of age and it's been really refreshing to have a laugh on set. But I have never before experienced corpsing; having to do take after take because you can't stop laughing. In the end we all developed this sideways glance when doing a take because you know if you look each other full in the eye you'll collapse with laughter."

In the series Stuart talks at length about his personal life with his fellow EMTs. Maxine doesn't have that outlet, as Amy explains: "Maxine has Ryan, her colleague in the force, but their relationship is quite professional and when they touch on personal things it's not comfortable. The scenes with Kobna Holdbrook-Smith who plays Ryan were great as he is a good friend of mine. We did a drama together called Whatever It Takes and he played my chauffeur so when I failed my driving test on this job Kobna had to do all the driving as Ryan. He said 'oh, it's driving Miss Daisy again.' It was really hard because when I got the job I hadn't had any driving lessons so I decided to do an intensive driving course. I was filming in Leeds then coming back to London and literally doing six hours a day with an instructor. It was driving me insane. When I failed the test I decided to focus on the job."

So with or without a driving licence could Amy have been a police woman? "Absolutely no way could I have been. Having to break down a door of a house where a schizophrenic guy is wielding a knife and having to disarm him is something I could never do. I would be petrified. I've gained a hell of a lot of respect for the police by playing Maxine, and getting to know what they go through, the sexism female officers encounter, not necessarily from colleagues but the outside world. I got it when we were filming and drunk guys would think I was a real policewoman and make sexual comments but if I was having to deal with that on a daily basis... no way!"