When a man is tired of London," Dr Johnson famously observed, "he is tired of life." That hoary old saying takes on an ironic new resonance for the characters in Michael Winterbottom's new film, Wonderland, all of whom are exasperated by the big, bad city. Laurence Coriat's labyrinthine, Short Cuts-style screenplay follows three generations of the same family. Bill (Jack Shepherd) and Eileen (Kika Markham) are trapped in a loveless marriage and estranged from their 21-year-old son (Enzo Cilenti).

One of their daughters, Debbie (Shirley Henderson), is chafing against the boredom of looking after her nine-year-old kid. Another, Nadia (Gina McKee), is using the lonely hearts columns to snare a man. Meanwhile, their third daughter, Molly (Molly Parker), is about to have her first child.

"What appealed to me about the script," says Winterbottom, "was that it created a picture of London which I recognised, but I hadn't seen on film before. That sense of the restlessness, of that constant battle which people have to keep their heads above water and, more importantly, to find some space and time in which to try and enjoy life."

In adapting Coriat's screenplay, Winterbottom and his producers, Michelle Camarda and Andrew Eaton, were determined to present the city in as gritty and realistic a light as possible. "The idea was to shoot with as small a crew as possible and to keep the whole film circus to a minimum," Eaton notes. "We wanted to go into real places, use real people and tell the story in what was almost a documentary style."

Cinematographer Sean Bobitt (whose background is in documentary) shot the film on Super 16 with a lightweight Aaton camera. He tried to use natural light wherever possible. Locations included Vauxhall, Clapham and South-East London's proverbially ugly landmark, The Elephant And Castle.

The skeleton crew also ventured incognito into the heart of Soho, filming late at night in crowded bars and clubs. "People in central London seem very used to camera crews," Eaton observes. "It was amazing how you could just go up to them. They wouldn't bat an eyelid."

Though Winterbottom stayed true to Coriat's dialogue, he encouraged improvisation across the cast and crew. The actors wore concealed radio mikes and often didn't know whether or not they were on camera. "Some of them found that a little unnerving to begin with," Eaton acknowledges, "but others took to it like a fish to water."

Although actors like Gina McKee (Naked, Notting Hill), Ian Hart (Backbeat, Land And Freedom) and Molly Parker (last seen cavorting with corpses in Lynne Stopkewich's Kissed) are relatively well-known, passers-by either didn't recognise them or pretended not to.

In all, more than 150 hours of footage were filmed - and the team claims that no two shots were ever the same. "We had a chance to show London in a way you don't normally get to see it," says Eaton. "If you close down a street and fill it with extras, it's never quite the same thing. That's what gives the film its emotion - the fact that you're watching real people."

Wonderland, which was originally developed by Michelle Kamarda's Kismet Films, is a joint production between BBC Films and PolyGram. Winterbottom boarded the project only weeks after finishing his previous feature, Old New Borrowed Blue (which was made for Film Four and Miramax.) This led to some bizarre contractual wrangling. Between 10am and noon during the overlap period between the two films, Winterbottom was on first-call to Old New Borrowed Blue. He could only devote his full attention to Wonderland after lunch.

"We went into one meeting at Film Four when Michael had just had his hair cut and there was a big row about whose time he had been using for that," Eaton remembers.

Editing one movie while shooting another would probably leave most film-makers feeling confused and schizophrenic, but Winterbottom seems to have relished juggling projects. "It's like a novelist who writes his novel in the morning and his screenplay in the evening," Eaton suggests. "'It's actually an inspiring way to work." Geoffrey Macnab