It’s late at night on the cobbled winter streets of East London, and the cast and crew of the ambitious new Britflick Franklyn are struggling with semantics. “It’s a somewhat arty philosophical science fiction romance thriller,” says the film’s 29-year-old star Sam Riley, hands deep in raincoat pockets, tongue only half in cheek, as he describes his first film since playing Joy Division’s Ian Curtis in the award-winning Control. But Franklyn, whose filming is due to culminate this very night in a side street shoot-out and rain-soaked reconciliation, is proving impossibly difficult to explain, to distil or to quantify.

The movie, which follows four separate yet intertwined narrative journeys that weave through both contemporary London and an futuristic dystopia, is, says its producer Jeremy Thomas (Sexy Beast), “Genre-busting, genre bending and genre breaking. It’s a genre of no genre.”

Over in the corner, the 28-year-old Casino Royale Bond Girl Eva Green has a go. “It’s a metaphysical movie about fate,” says the pale-eyed beauty. “People who only know me as Vesper from Bond are going to be quite shocked.”

Her writer-director, the promo and commercials veteran Gerald McMorrow, strolls by and offers: “It’s an urban fairytale fantasy drama, with a parallel world aspect to it.”

Cut to 14 months later and the prospect of pigeon-holing Franklyn remains elusive. The movie’s narrative ostensibly follows a gloomy lover called Milo (Riley) who’s been jilted at the altar, but who catches glimpses of an old childhood sweetheart, Sally (Green), drifting through his London haunts. Sally is the double of a suicidal video artist called Emilia (also Green) who has a penchant for filming her own attempted overdoses on camera. Emilia’s plans for a final reel blowout, however, are interrupted when the man in the flat upstairs turns out to be a part-time comic book anti-hero called Preest (Ryan Phillippe), who lives mostly in a dark futureworld that looks like something from a medieval Blade Runner, is called Meanwhile City and is populated by religious zealots.

“When you’re writing and putting together something like this you know that it’s not going to be easy for the marketing department,” explains McMurrow, 38, who cut his teeth on pop promos for Catatonia and commercials for AOL before directing the award-winning short Thespian X (a futuristic sci-fi parable). “But you have to retain a certain naivety, not worry about that, and just keep going.”

This, he adds, mostly involved using the movie’s £7 million budget to transform London locations into credible future spaces. The rooftops of the Victoria & Albert Museum played a part in a key nightscape scene, while Greenwich Naval College became Meanwhile City’s main street.

Both hot up and comers, Riley and Green leapt at the chance to steer away from the mainstream. Green says: “I hadn’t done much and had a lot to prove, so something like this was far more challenging and better for your soul than the big movie machines.”

Surprisingly, the finished Franklyn actually makes a lot of sense. The seemingly disparate narrative strands mostly come together in a satisfying closing act. And yet it’s the thematic hints, the narrative fractures and the curious visual diversions (what were those tattoos on his back? What does the Renaissance tableau mean? Who is the janitor?) that make it such a perplexing experience — one likely to motivate devotion and derision in equal measure. “But I like films like that,” says McMorrow, hinting that Franklyn might require a second viewing before it even begins to reveal itself. “The first thing I did after seeing Michael Haneke’s Hidden was go back and see it all over again. I like films that draw you back to them, because life isn’t perfect and things don’t ever tie up neatly.”

Riley, who has since starred opposite Mickey Rourke and 50 Cent (“Or Two Bob, as I like to call him”) in the forthcoming Russian roulette drama 13, is similarly convinced that we should embrace the enigma in Franklyn, not hide from it. “You come out of it going, ‘I’m not really sure what I’ve just seen’,” he says. “It’s the alternative to the alternative.”

Thomas, who won a Best Picture Oscar for The Last Emperor, says that he has no illusions about how Franklyn will fare when dropped into the marketplace against “traditional” comic-book extravaganzas such as Watchmen (“It had 20 times our budget”), but that he still hopes to find an audience. “I never intended this film to challenge Watchmen or Batman,” he says. “It’s like the corner shop trying to deal with Tesco. But that doesn’t mean that the corner shop can’t be very successful.”

McMorrow, in the meantime, shows no signs of restraining his wilder impulses, and is working on three new projects, including a full-length animation and a thriller about Native Americans, but set in Manhattan. He says that he hopes Franklyn will show other aspiring British film-makers that they can do more besides “Richard Curtis comedies and mockney gangster movies. You can get out there and start experimenting, tell stranger, weirder stories. And if it doesn’t work it’s not a disaster. It’s just important to be able to try.”

Franklyn is released on Feb 27

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