When 23 Chinese cockle-pickers drowned in Morecambe Bay in February 2004, the British media were slow to grasp the scale of the tragedy: it was seen as a "Chinese" issue. The Chinese community, too, was largely silent. I remember distinctly an argument I had with a Chinese artist who saw the cocklers as being a class below him. "They were responsible for their own deaths - who told them to be smuggled here?" he said.
Saddened by such attitudes and by the media's response to the Morecambe deaths, I decided to work undercover with a group of undocumented Chinese workers to gain an understanding at first hand of their working lives in Britain. It took me more than two weeks to get the work-permit photocopy and the contact number for the recruiter in Norfolk that would enable me to enter this hidden world.
There, in the country town of Thetford, I witnessed almost unbelievable exploitation. Legitimate British agencies were taking advantage of the unauthorised status of workers, employing them as a half-price army of labour to run the food-processing factories that supply supermarkets. I witnessed how these men and women risked their health and safety to improve the lives of their families, how they struggled from day to day with ruthless exploitation in a first-world country. They lived in social isolation, suffering constant insecurity and anxiety.
My undercover news report encouraged wider reflection on the issue. TV programme-makers and film directors began to call. Some wanted to take a snapshot of the workers' lives. Others were simply looking for sensational stories. But the proposal which interested me most was from the documentary-maker Nick Broomfield. His film about Morecambe, Ghosts, is released this coming week. It should be a timely reminder that, in many ways, the lessons of that terrible day still have not been learned.
Nowhere is this illustrated more graphically than in the story of 28-year-old Aiqin Lin, who plays the lead role. Broomfield found her after a painstaking six-month casting process and knew at once that she was the one. His film traces the fictionalised story of one of the cocklers from her home in China to the bleak sands of Morecambe. Aiqin endows the role with an eerie authenticity, largely because the tragedy shown on screen could easily have been hers.
Aiqin's story mirrors that of so many undocumented Chinese workers in Britain (it is estimated that there are more than 70,000 of these). She comes from Jinfen, an industrially depressed small town near Changle, in Fujian Province. It has a population of 30,000, mainly under the age of ten or over 60, as the younger adults from almost every family are being or have been smuggled abroad. Career opportunities are scarce, and work is confined to low-pay, dead-end jobs in service industries and the garment trade.
Aiqin came from a poor background, with a family that struggled to cover its costs. Having tried but failed to start her own business, she was tempted by tales of prosperity in England and so borrowed heavily to pay local Snakeheads the equivalent of $25,000 to arrange her journey. "No one wants to take a risky route. But what alternative have we got?" she asks. "We Fujianese don't stand a chance of getting a proper visa - the British government sees us as bogus. There was simply no legal means to enter Britain."
The gruelling journey took four months. The Snakeheads arranged fake passports and took Aiqin and four others across China to Shenyang in the north-east. Here they were met by another Snakehead, who got them on a plane to Moscow. From there, they travelled to Ukraine by train, with little food and no clean water. A month later, they moved again - this time to the Czech Republic. "There, I was put in a poorly equipped flat with 20 other people from different countries, some of whom had been waiting for two years to get to their final destination in Britain. I was so frightened that I might end up waiting as long as them.
"Following a long month waiting, I felt relieved when we were finally put on a lorry heading for Holland. We were in a tiny sitting space, squeezed between 50 others. We were hungry most of our way. Occasionally, the driver threw some bread into the back of the lorry to feed us. I was beginning to feel ill."
It was March 1998 when Aiqin finally arrived in London. The Snakeheads took back her passport and simply dumped her outside Liverpool Street Tube station. It took four months to find her first job, at a fish-and-chip takeaway, and she later worked in a garment factory for £2.50 an hour, 80 hours a week. "I worked and worked till I couldn't feel anything. The moneylenders were on my back, so I accepted anything from the London boss. He knew how to use our illegal status to his advantage."
She became pregnant, and her boss refused to pay her wages. "When my son was born, I knew that I couldn't keep him with me in England. I was still in debt. I couldn't afford to bring him up here. I tried. I was selling prawn crackers in paper bags on the street to make up for my earnings, and got kicked out of shopping malls.
"In the end, I had to ask a friend who I knew through the church to take my son back to China," she says. "He was only a year old then. It hurt me more than anything else."
The part in Ghosts has already transformed her life. She and the film crew went on a two-week trip to Jinfen, where she was reunited with her son and her mother. Having been separated from Aiqin since he was a baby, her five-year-old son did not recognise her. It is a scene that is painfully played out in Broomfield's film.
Aiqin now has permanent residency in Britain, and her son has joined her. "Maybe Ghosts will help the British people understand us," she says. "I do hope so."
"Ghosts" is released on 12 January