Young love runs free in Sightseers. Perhaps too free. And it certainly comes with too much murderous anger. Think Badlands in the Midlands, in knitted crotchless knickers and wielding a giant pencil.

Sightseers' lead characters Chris and Tina are spree killers in a Caravan, hitting the byways and B-roads across the belly of England. They were first developed by Alice Lowe and Steve Oram through live character comedy, then starred in a short film and now, with thanks to Kill List's Ben Wheatley and Amy Jump, have made the transition to a big screen feature.

Lowe and Oram's original screenplay was rewritten by Jump and reworked by Wheatley, but it's this duo still at the heart of the film, providing the odd energies that bring Chris and Tina to life.

I sat down to talk to them a couple of weeks ago. Here is some of what they had to say.

Alice:We were interested in this idea of the stereotype of Britishness, and British tourists, which is this polite veneer, very friendly "Oh I'm sorry that you trod on my toe" thing. We wanted to do something that confounded that, and that translated really well to a film idea - very normal characters but in a very extraordinary situation. It's very filmic as well with murder, sex, violence, all of those things. The meat of drama.

We knew that Chris and Tina had to have realistic psychologies for you to even go half way to understanding them. If you didn't empathise with them you wouldn't want to spend time with them on this journey. You'd be disgusted by them. We knew there had to be some psychological reason why they were the way they were - they had to be damaged people. What had led them to this particular scenario, and their coming together had obviously triggered something else as well. So that's the whole concept of the movie - two people coming together and becoming more than the sum of their parts.

Steve:There's no real moral message. We're just showing people honestly We did loads of research into serial killers, and we wanted them to feel like realistic serial killers.We had a responsibility, I think, as filmmakers, to not treat these things flippantly. It happens and it's horrible.

It's stuff like Fred West doing DIY for his neighbours, and being a bit of 'a character.' People liked him on the street, which is astonishing when you think of what he did. I met someone who went for a drink with Dennis Nilsen, in a group of friends. Just thinking that 'they' are all around us, everywhere.

Alice:We didn't want to make a light, Carry On-style murder comedy, we wanted it to have some psychological veracity to it. And to challenge people - I don't think you watch the film and feel they get off scot free. They are punished in the end for their transgressions, in quite a classical way.

You can take the film in a metaphorical way if you wanted to; these killings are a metaphor for the relationship going wrong. It's also quite cathartic. I wonder if people are enjoying it as it's two people who are 'outsidery' and failing in their life and they get to do what they want to do. It has that worm that turned kind of element to it.

Steve: Chris hasgot that morality, but it's total bullshit. When you look at serial killers they're just really into themselves. They're very "me" people. They think they're playing God, and they're just making up the rules.

Alice:And Tina as a serial killer is much more creative. She genuinely wants chaos. That totally fucks around with Chris' world, but also adds an exciting element. He decides he would rather not be alone, and would rather have a partner in crime if that person loves him. There's an element of pathos to Chris' character. He does love her. That's the redemption to both these characters; that they are in love.

Sightseers is released across the UK on Friday November 30th.Go with someone you love.