Filming was due to start on Hot Fuzz in April of 2006 and there were still 56 speaking roles to cast. What’s impressive is who the duo bagged to fill those roles.

Some were pulled from Wright and Pegg's rolodex - Bill Bailey had appeared in Spaced (and Black Books, which Park produced), while Bill Nighy and Martin Freeman had both appeared in Shaun Of The Dead.

For most of the other characters, they cast their nets slightly further afield (including two major cameos by two Oscar-winners that you should keep an eye out for), casting venerable British character actors, including Timothy Dalton as supermarket manager Simon Skinner and Jim Broadbent as Sandford Inspector Frank Butterman. Happily, their first choices for each role proved up for the job.

"We always have a cast in mind," says Pegg. "I remember one day in the green room just looking around and going; 'there's Belloq from Raiders of the Lost Ark [Paul Freeman], Mrs. Baylock from The Omen [Billie Whitelaw] and The Equaliser [Edward Woodward]' I was in geek heaven."

"The idea is that in Sandford, alongside the police, you also have the busybody Neighbourhood Watch Alliance," says Pegg. "They're the village elders. Almost everyone in Sandford has a name that relates to outdated country professions such as Hatcher, Shooter, Weaver, etc.

We wanted to build up a sense that it was a village that people never left, that their ancestors had lived there for generations and been those original artisans.

The two CID officers, Wainwright and Cartwright, played by Paddy Considine and Rafe Spall, (one of the acting returnees from Shaun of the Dead) are just as much part of this tradition, however much they distance themselves from it.

We wanted to reinforce the sense that Angel had entered a place steeped in incestuous tradition."

As for the buddy cop duo of Nicholas Angel and Danny Butterman, there was never any doubt who'd fill those shoes: Pegg and his real-life best friend (and best man), Nick Frost. "They're just a brilliant comic act on screen, so they have to be buddy cops!" laughs Wright. "Not that they're buddy cops all the way through. Nick's character likes Simon from the beginning, it just isn’t reciprocated!"

This twist on the standard buddy formula sums up Hot Fuzz's modus operandi: plunder the genre conventions and then upend them.

This applied as much to the character of Nicholas Angel, who gets transferred to Sandford at the beginning of the movie because he is just too good at his job. "In all those seminal cop films, someone gets demoted or sent away because they fucked up or killed somebody," laughs Wright.

"We'd written the script and the character of Nicholas Angel, whose arrest record is 400% higher than any of his other officers in the Met and rather than being commended for his efforts, he's sidelined."

For Pegg, Angel posed the biggest challenge of his career. "I couldn't rely on any of my tricks with him because he's not goofy," he admits.

"He's absolutely focused all the time. You don't see him smile until halfway through the film. He's like a robot.

You could argue that in Shaun I was just doing a different version of Tim [from Spaced], or more accurately a version of myself, whereas with Hot Fuzz it was a total change.”

However, one crucial element does carry over from Spaced and Shaun Of The Dead: Pegg and Frost would play (eventual) best friends, and their off-screen chemistry helped Pegg enormously.

"Nick was always a part of the equation, always always. We're tied to him. He's a secret weapon, Nick," explains Pegg. "It's very easy to write for Nick. I always thought he was the funniest guy I knew.

He's a very natural talent and funny and we have a really good onscreen relationship in that we are best friends and can really bounce off each other well."

Although Frost wasn't directly involved with the script-writing process, he was kept in the loop by Pegg and Wright throughout, and was able to make key contributions. "I came up with the name Danny Butterman," reveals Frost.

"I said I would only do it if I could call him Danny Butterman. It was a name I'd been thinking of, I wrote it down a while ago. It has a nice Hobbiton feel to it. Simon and Edgar are quite happy for me to come in with suggestions.”

As with Angel for Pegg, Butterman is unlike anyone Frost has played before. The son of Broadbent's police chief, Danny is a likeable but naïve young officer, a huge action movie buff who has never seen action but would like to.

"Danny's enthusiastic about being alive!" laughs Frost. "Jim Broadbent said that he'd never seen a more enthusiastic man than Danny, and I think that's true.

He's with his dad and there's no crime and he doesn't have to work, but he gets to wear a uniform. He plays a lot of rugby, he goes to Bristol Rovers, he's got a really nice life. And then when Nicholas Angel comes down to Sandford, he sees in Nicholas everything he always wanted to be.

I think Danny would run a mile if somebody pulled a Kalashnikov out on him, but he likes to think that he wouldn't. He talks a good game!"