THE answer to life, the Universe and everything is 42. The rudest word in the galaxy is Belgium. And a Pan Galactic Gargle Blaster should always be drunk with extreme care. We know all this and more thanks to The Hitchhiker’s Guide to the Galaxy.

We first heard of this indispensable tome in Douglas Adams’s 1978 BBC radio comedy serial in which the pyjama-clad earthling Arthur Dent was catapulted into intergalactic adventures after his home planet was destroyed by the Vogons to make way for a hyperspace bypass. It spawned more radio serials, a TV version, a concept album, a stage production, a “trilogy” of five novels, even a novelty towel.

Now it’s a feature film, but Adams isn’t here to see it; he died in 2001, aged 49, in California while still labouring on the screenplay. His draft scripts were later shaped into a workable narrative by Karey Kirkpatrick (Chicken Run). And it’s that version that landed on the desk of the British producer Nick Goldsmith, 34, and his directing partner Garth Jennings, 32.

Describing themselves as “Adams fans but not purists”, they say the script’s route to them has been “mental”. Ivan Reitman (Ghostbusters) originally took an option on Adams’s story in 1982 and imagined it as a spoof Star Wars (Mel Brooks’s Spaceballs suggests how awful that might have been). Directors as varied as James Cameron and Terry Jones of Monty Python came in and out of Adams’s orbit.

Then, in 1997, Adams signed with Disney via Spyglass Pictures and another cycle of Hollywood development hell began. By the time of Adams’s fatal heart attack, the director Jay Roach (Austin Powers) felt more comfortable as a producer and asked Spike Jonze (Being John Malkovich) to direct. He in turn recommended Goldsmith and Jennings. Through their company Hammer and Tongs the duo has made their mark with such offbeat pop videos as Blur’s Coffee and TV (featuring an animated milk carton) and Fatboy Slim’s Right Here Right Now (single cell creatures evolving into lazy humans).

“Douglas always looks to the left of a scene that gives you the bigger picture,” says Goldsmith. “Our stuff is like that too.”

Adams was always reimagining the Hitchhiker story; the film has the new character of a crazed religious cult leader, played by John Malkovich. “So we’ve felt free to add little touches of our own,” says Goldsmith. “We’ve tightened the plotting and made Arthur less passive, so he now has a relationship with his unrequited love, Trillian, and has to rescue her from the Vogons.”

Shortly before his death, Adams reportedly wanted Hugh Grant as Dent, while other possible Arthurs over the years have included Rowan Atkinson and Jim Carrey, but the role went to the blokey everyman Martin Freeman (The Office). “We all agreed early on that the star of the movie is the title,” says Jennings. “So it was never a case of trying to get Tom Cruise.”

The other main cast members — Sam Rockwell as the galactic president and fugitive Zaphod Beeblebrox, Zooey Deschanel as Trillian, and the hip-hop star Mos Def as Arthur’s alien friend, Ford Prefect — are better known from American indie films. Was that deliberate? “No, it just happened that way,” says Goldsmith. “The cast had to click as an ensemble. Martin can make anything bizarre seem plausible. Zooey’s demeanour is naturally deadpan and off the wall. Mos is wonderfully laid-back. Sam originally auditioned for Ford but wanted to play Zaphod and he became this cross between Freddie Mercury and Bill Clinton. It all made sense.”

But has the quirky English sensibility of the story, in which finding a decent cup of tea can be more important than an exploding planet, survived this American influx? “The whole cast understood the humour very quickly — that hopping through the galaxy is quite mundane,” says Jennings. “I seldom had to say: ‘Don’t do the Harry Potter face’.”

Goldsmith adds that there’s a strong British tone. Besides Freeman, Bill Nighy plays the planet designer Slartibartfast (fjords a speciality). Vocal support includes Alan Rickman as the paranoid android Marvin and Stephen Fry as the Book.

The film’s look was also important. “We wanted to match Douglas’s surreal slant on the everyday,” says Goldsmith. “We kept saying to our designers: ‘Less Star Wars, more Yellow Submarine.’ Zaphod’s ship, the Heart of Gold, is actually based on Garth’s office teacup. Opposite us is a warehouse that inspired a Vogon ship.”

Jennings adds: “We saw the Vogons as these dilapidated bureaucrats and James Gillray’s work — all those swollen bodies and useless arms — came to mind.”

The use of computer-generated (CG) effects is relatively sparing. “This is a comedy so it was important that all the characters, however freakish and weird, physically interacted with each other,” says Jennings. “We could tart up scenes with CG later.”

Apart from the unpredictable British weather, he says that making his first feature film has been “a blast”. But he and Goldsmith are now looking forward to the project they were working on before Hitchhiker took two years of their lives. “It’s a coming-of-age story about two teenagers in the 1980s,” he says. But isn’t that rather conventional? Maybe not. “It’s called Son of Rambo.”

• The Hitchhiker’s Guide to the Galaxy opens on April 28

  LOVING THE ALIEN AND OTHER SCI-FI CLICHÉS

• Our future world is a rain-lashed metropolis

  of recognisable brands, Big Brother-style PA announcements, flying cars, and sleazy nightclubs with mutant dancers and funny coloured drinks.

• The explosions are always bigger than the last film.

Explore Film

• Film Reviews

• Trailers

• DVD

• London Film Festival

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010