Documentary maker Nick Broomfield talks to Donald Clarkeabout his moving feature film based on the 23 Chinese cockle pickers who drowned off a Lancashire beach in 2004

WHEN, late last year, Nick Broomfield, the cut-glass English documentarist, released a film addressing the awful story of the 23 Chinese cockle pickers who were drowned off a Lancashire beach in 2004, we heard surprisingly little grumbling from the director's many detractors in the media. Since he sauntered out of film school in the early 1970s, Broomfield has annoyed and entranced viewers with his singular films on subjects such as the Liverpool rent strike, the South African white supremacist Eugene Terre'Blanche and the serial murderer Aileen Wuornos. Fans praise his talent for persuading subjects to blurt out quite staggering indiscretions. Enemies suggest that Broomfield, a dark man who speaks in a staggeringly posh drawl, too often allows himself to become a central character in the drama.

Such criticisms do not apply to Ghosts. For only the second time in his career - the first was 1989's disastrous Diamond Skulls - Broomfield has elected to tell his story in a dramatic feature.

"Well I wanted to do something on the subject of modern slavery, as this is the 200th anniversary of the abolition of slavery," he says.

"There are more slaves now than there ever have been. Not shackled, but indentured all the same. The immigrants who are brought over here have huge debts and no freedom of movement." Interesting. It sounds like a good subject for a documentary.

"Yeah, you do see some surveillance-camera footage of the immigrants occasionally. But it just would not be practical to follow illegal immigrants across three continents. How could you? Drama is a more appropriate medium. Drama is better at dealing with the emotional story of these people left in a country they don't know."

Ghosts never received a theatrical release in this country. Now that it is available on DVD, domestic viewers can judge for themselves the extent to which the director has retained the techniques and style of his documentary features. Shot on video with a tiny crew, the film follows a young woman from a remote Chinese province, who, frustrated by her inability to support her baby, makes the horrific journey to Britain to endure a life slaving in meat-packing factories, vegetable fields and, ultimately, those perilous cockle beds. The actors - notably Ai Qin Lin in the lead - are amateurs and the locations are grimily genuine. Screw up your eyes and you could take Ghosts for a documentary.

"I didn't alter my practices that much, but I altered a lot of other people's practices," he laughs. "Sometimes painfully so. We didn't want to use a tank for the scenes in the water, so that is shot in quite dangerous circumstances. I wanted to make everything as authentic as possible. So we really used Morecambe Bay. These things make it all the more believable. Ai Qin Lin was herself smuggled into Britain, so I was able to use the emotions she had felt then." Indeed so. And the picture features one especially moving scene in which Lin, returning to China, is introduced to her own infant daughter for the first time in five years. The sequence allows us to believe that this is the film's central character hugging her child, but the grain of the image and the raw emotion on display make it clear this is the real thing.

"If we hadn't been there Ai Qin Lin would not have got home to China at all," Broomfield says. "We spent months at the Home Office getting the various necessary documents. Otherwise, she would still be in this country having not seen her kid."

Moving as this sequence is, it does inspire some of the old questions about Broomfield's techniques. Is it proper for us to watch the homecoming as entertainment? Was there a degree of staging? Nick Broomfield infuriates many documentary purists. More than anything else, they object to the way he inserts his own persona - disingenuously baffled posh boy - into most every film he makes.

"Broomfield" is not visible in the verité sequence in Ghosts, but he is everywhere in The Leader, His Driver and The Driver's Wife, the Terre'Blanche film, and Tracking Down Maggie, a humorous pursuit of Margaret Thatcher.

"Those critics are just way out of date," he says. "And completely incorrect. You are always part of the process. My appearance is an acknowledgment of that. And your relationship with the subject is the dominant influence on the film. To pretend you are not there is ridiculous."

What about the criticism that the Broomfield we see in his films is a creation? Though his mother is Czech and his father was a self-made man, Nick sounds like a character you might encounter lurking in the background of a P G Wodehouse book. Moreover, like the superficially similar Louis Theroux, he does have a habit of presenting a suspiciously dumb façade to his subjects. One suspects that Terre'Blanche and others would be less threatened by an apparent boob than they would be by some sleek media operator.

"You do occasionally have to adopt a persona," he agrees. "But in America they can't tell one English accent from another. And I haven't really made many films here, so the class thing is rarely important.

"But, as a film-maker, you make advantageous use of whatever accent you have. Obviously, I use it as a way of being more of a stranger. I demonstrate that I am not part of the group I am filming."

Now 59, Broomfield, for all his detractors, has established himself as a reliable cinematic brand. Formerly a boyfriend of such glamour-pusses as Gina Bellman and Amanda Donohoe, he lives contentedly in rural Sussex on a vast property comprising five separate buildings. A box set of his early works is available. His style is sufficiently recognisable that he may soon find his name turned into an adjective. So what if not quite everybody loves him.

Ghosts is out now on DVD

Tide of tragedy: That day in Morecambe

On February 4th, 2004, 23 migrant workers, all illegal immigrants from China, were drowned in rising tides while picking cockles off Morecambe Bay in Lancashire. Two years later, Lin Liang Ren, another Chinese national, was convicted of their manslaughter. During the trial of the so-called gangmaster, it was revealed that Lin, working with only half his usual workforce, was so desperate to collect two truckloads of cockles that he neglected to bring the team home before the tide came in. Only one of the workers survived to tell the tale, but several more made harrowing phonecalls home to relatives as the waters began to rise. "Tell the family to pray for me. It's too close. I am dying," Guo Bin Long, one victim, said to his wife.

At a pre-trial hearing, the British government was seriously criticised for failing to do enough to stop the "shadow industry" of cockle picking by unregistered migrants.