THE GLOBAL SWEATSHOP: Gap shorts cost pounds 28, but the hard labour of women who made them costs just 20p

The Independent's campaign against sweatshops will urge retailers to ensure workers employed by their suppliers and subcontractors do not suffer through low wages, long hours and poor conditions. We ask them to put in place codes of conduct and to have them independently and rigorously monitored.

AT 6AM the daunting 7ft-high metal gate of the Tack Fat garment factory slides open a few reluctant inches to release hundreds of nightshift workers, who trickle out on to one of Phnom Penh's busiest roads, bleary- eyed and blinking in the grey morning light.

Few of the Cambodian workers know it, but the clothes they sew and iron will eventually bear the labels of Gap and C&A. Nearly every item will sell for more than they earn in a month. The starting wage here is pounds 5 per week, rising to pounds 6.50 after training. A pair of Cambodian-made shorts bought in a London Gap store by The Independent cost pounds 28. The labour cost is estimated at less than 20p. Economists say the Cambodian poverty line is pounds 11 a week.

Most of the 3,000 workers here are young women, in brightly coloured jackets - blue for sewing, green for checking. After the night shift, many pick their way through the food vendors and turn down a muddy, pot- holed alley down the side of the factory wall. At the end lies a stagnant, mosquito-infested swamp surrounded by a confusion of wooden shacks, their homes. The air is heavy with the stench of raw sewage.

Here, three sisters share a damp, one-room hovel with their mother, for which they pay pounds 13 per month. The only furnishing in the dirt-floored room are two slatted bamboo benches on which they sleep. Their clothes hang from a string behind the door.

They giggle when asked their ages. The minimum age for employment is 15 but there are exemptions, and there is no official register of birth. Getting straight answers here is difficult - some women are not clear how much they earn.

Other workers are more forthcoming. Himsour is 26 and came from the countryside to look for work in the city, as do most workers. She earns a basic wage of pounds 26.60 per month and shares a tiny room with two men. They pay pounds 3.30 a month each. Sopheak, 27, earns the same and lives with his brothers. Bounang, 27, is luckier. He is experienced and earns pounds 46 basic. They all try to send money home.

All three say they have to work at least two hours' overtime every day for an extra pounds 6.60 a month. "We never know what time we'll finish - sometimes we work 14 hours, till 9pm, with just an hour off for lunch." Money is deducted from their wages for lunch, even if they eat outside. "The factory food often makes us sick," they say.

If there's an inspection they are told what to say, they claim. "If we told the truth we'd get fired," says Sopheak. Bounang says he has worked for two years without a holiday. "When I asked for two days off they cut my salary."

All agree the female workers are worse off. "Some only earn pounds 20 a month. They have to get their card stamped when they go to the toilet and sometimes they faint from exhaustion and the heat."

Outside these shacks more uniformed young women stand around, combing their hair and chatting before they leave for the 7am dayshift - that's a minimum nine hours, shows one woman's card, carefully stamped with the exact times she has entered and left the factory this week.

Most days they work at least two hours' overtime on top of that, which, they say, earns them an extra 24 pence a day. Cambodia is a desperately impoverished, predominantly agrarian country, saddled with the aftermath of 20 years of warfare and internal strife. Its rapidly expanding textile industry is in its infancy. Three years ago there were 30 garment factories; today there are at least 180, providing jobs for 168,000 people who would otherwise be trying to eke out a living in the countryside.

The labour costs are attractive. In increasing numbers the investors have come: Nike, Gap and Levi among others. Some local campaigners say they are exploiting a cowed workforce with no choices, no rights and no voice.

Sam Rainsy, the leader of one of Cambodia's Opposition parties, says conditions in garment factories have improved, but very little. "Let's put the standard at 10," he says. "Then they were at zero. Now they are at two. Many of the changes are cosmetic."

Three years ago, conditions in many factories were so appalling workers could no longer tolerate them: pay was pounds 13 a month, there was forced overtime, child labour, physical and verbal abuse, summary dismissals, no sick leave.

A flurry of strikes followed - including a series at Tack Fat, starting in January, 1997. Mr Sam had accused the factory of having some of the worst conditions. Earlier this year, workers were still complaining about Tack Fat. During a visit by US trade representatives, they said, youthful- looking workers were told to hide in the toilet; others were told to work slowly and go home at 4pm. Fear of losing their jobs stopped complaints, they said.

Van Sou Ieng, chairman of the Garment Manufacturers Association, admits there are "bad apples" among his colleagues. "Some don't understand the labour law but most comply with it. If they don't, the association won't support them. Some of the workers have unrealistic demands - like asking for 40-hour, five-day weeks. The Cambodian garment industry is three years old. They know nothing. Maybe in 10 years." Gap and C&A said they had done social auditing at the Tack Fat factory recently, and although C&A said it detected problems and intended to visit again soon, Gap was satisfied with what it found. Gap said its inspectors talked to workers, and those from C&A did not do formal interviews, though they encouraged workers to send them e-mails in confidence if they had complaints. No one said where the workers would find computers. Neither company inspected living conditions, though C&A said the factory had clean kitchens.

With workers earning just pounds 26 a month, a C&A spokesman was asked why a living wage could not be paid. He said a British family could not live on the UK minimum wage of pounds 3.60 an hour. "Each has to bring something into the household," he added. "In that sense, nobody has to earn a living wage."

The spokesman said some workers earned pounds 55 a month.

n Names of the workers have been changed to protect them