With its iconic theme music, beloved catchphrases and supersized arrows, the classic BBC comedy offered Dad's Army plenty of opportunity to pay playful homage. For director Oliver Parker, writer Hamish McColl and the cast, though, those nods to the television series had to fit seamlessly into the movie. "It's about getting the right balance," points out the screenwriter of using those famous lines. "My idea was to keep them select, rather than bombarding the script with catchphrases."

Bill Paterson - whose character, Private Frazer, was famous for muttering "we're doomed!" at moments of crisis - points out that those iconic sayings evolved over the comedy's nine-year span. "That's how a catchphrase comes into being," he stresses. "You don't get it instantly." The movie adopts a similar tact with nods earned rather than merely crowbarred in for an easy laugh. "I felt we couldn't use the 'doomed' one until it looked like we really were doomed. Likewise, we held back 'they don't like it up 'em', 'don't panic' and 'stupid boy' until they'd been earned. They come at a time when that's exactly what should be said. It's a very fine line when you do something like this. You're trying to recreate the Sistine Chapel." Adds McColl: "It's about finding the best moment for them and not over-egging it."

An Ian Lavender cameo provides another strand of the show's original DNA. "I had a chat with Ian on set," remembers Blake Harrison, "and he's really lovely and really good in the film too". The conversation didn't extend to tips for playing Pike. "We're making changes and a lot of what I wanted to know is already documented," he adds. "Plus, Ian's done nine series playing the character!"

Eagle-eyed fashionistas will quickly spot one of those changes. Pike's scarf, originally claret and blue, now has yellow bands too. Before Dad's Army diehards take up pitchforks, the reasons behind the addition are football-related. Lavender was an Aston Villa fan; Harrison supports Millwall. "I modified the scarf slightly, just to take it away from West Ham's colours a bit," laughs Harrison.

Frank Williams, the show's vicar, reprises his role on the big screen. Even those famous German arrows make an appearance, albeit shifted from the opening credits to a subtler spot within the first act. "They come in a scene when the Germans are looking at an invasion map and they're pushing these arrows around it," reveals McColl. "We've also used the 'You Have Been Watching...' caption [in the final credits] because it's so lovely."

When and where to use the iconic Bud Flanagan/Jimmy Perry theme tune was another question to be figured out. Again, there was a sense among the filmmakers that their big musical moment had to be earned over the span of the movie, although Charlie Mole's score foreshadows it at earlier moments. "The theme threads its way through as a riff, if you're listening for it," says Oliver Parker, "and at a certain moment right at the end we let it out. It carries such emotional clout and it was incredible at the testing. It's such an old dear friend. Bud Flanagan captured the period in a way that's almost impossible to replicate." The director credits his composer with nailing the tone of the piece. "He's really good at getting inside a genre and period," he says. "He wrote a marching song which we use a lot."

The Making Of Dad's Army 2016:

Creation

Casting

Rehersals

Hommages

On Set

Characters