With its combination of car chases, fist fights, gunplay, horse-riding, and general athleticism, Pegg knew that Hot Fuzz would present something of a physical challenge for him as an actor.

Not that it necessarily occurred to him while writing it. "When you write, you're just writing specifically from the point of view of a particular character," he explains.

"When I was doubled up in agony because I'd strained both my quad muscles running down the High Street, I was thinking 'you fucking bastard! Why did you write this ten mile chase sequence for Angel!' but at the time of writing you're just thinking about what's going to look good on-screen, you almost forget that it's going to be you who has to do the running."

To get into shape for filming, Pegg embarked upon a period of intensive physical training that required the attention of no fewer than three personal trainers and a strict diet that forbade him from eating after 8pm during shooting.

During location shooting in Wells, he also decided to run the two miles from the rented cottage he shared with Frost to unit base every morning. Frost, on the other hand, decided that for his character, a strict physical regimen wasn't a necessity. He took the car. "I would wave to Simon as we drove past," he recalls. "I never once stopped to give him a lift!"

Frost's maverick approach to preparation also saw him ignore a list of movies that Pegg and Wright gave him to watch.

"I saw Bad Boys 2 and that was it," he admits. But once it came down to the serious business of handling guns, Frost loved every minute. "I love guns. I love rough and tumble," he says.

"I've been practising being an action hero for 25 years. It felt great. I always try to take these things in my stride but when you've got two lovely handguns, you’re wearing a flak jacket and your best mate’s beside you, you can't help but walk with a swagger."

In fact, Frost and Pegg got so fond of their guns they christened them 'Emma' and 'Sarah'...

Fuzz on Location - Shooting in Wells

Although Hot Fuzz started filming in London, the brunt of the shoot mirrored the events of the movie and moved to a quiet, beautiful West Country location: Wright's home town of Wells.

The director claims that this hadn't been his intention from the off. "Subconsciously, maybe," he tentatively admits. "Wells is a city and the fictional Sandford is a village, so we were making it look smaller than it is. But it was good for us, being there."

With its cathedral, regular market and cobbled streets, Wells was a perfect choice to stand in for the tranquil (although much smaller) Sandford, but even when Wright moved it onto his wishlist, he didn't think it was a viable choice.

"I thought it would be too expensive - it's quite a tourist destination and it has the cathedral and twice weekly markets and so I thought it would be quite difficult," he continues. "We went on a location scout last year around Devon, Dorset, Cornwall, Wiltshire and Gloucestershire, looking for places. We had a shortlist and then ironically Wells was the one that was the most receptive."

Once filming began, the production crew - many of whom have worked with the team since Spaced, reinforcing the familial feeling on set -  frequently had to shut down the town square and surrounding streets to shoot major setpieces, from a massive, pivotal church fete scene requiring masses of extras, to action sequences and shoot-outs galore, while the ever-present spectre of rain ("the real reason why they don't make action movies in Britain," grumbles Wright) pushed filming back by a few days.

But the denizens of Wells took it all in their stride, with the local am-dram society helping out when a casting crisis arose at the eleventh hour, while local crowds weren't fazed by staged gunfights and the sight of Pegg riding through the town square on a horse.

Wright spent a fair amount of time greeting old friends, teachers and his visiting parents. "On the first day there, we were doing a night shoot right in the middle of the town square.

At 11pm, people were still watching the filming," he remembers. "But by midnight, it was completely deserted. Not just no people but no cars. It was so weird being back in your hometown with it feeling like a massive set because there was nobody there!"