IN the chaos of weekend arrivals at Hualampong station, a constant stream of young people leaves the trains and passes into the night, their lives signed away for the price of a restaurant meal. Children as young as seven or eight are bartered like produce to factory owners and brothel-keepers in the darkened streets outside, condemned to the fate of Thailand's lost generation of youth. As the worst drought for a century turns farmland in Thailand and neighbouring regions into a dust-bowl, the influx of children looking for work to support their impoverished families is turning into a deluge. Social workers fear that 300,000 children will slip into the child labour market in coming months, travelling from as far away as southern China and Burma in pursuit of Thailand's economic dream. Some, like Mia, a tiny Lao-Chinese in her early teens, will end up in brothels, seduced into selling their bodies by greed and a misplaced sense of family loyalty. ''I don't like it, but it is the only way I can help my family. My brother told me to come here and it is expected of me, so I do it,'' she said. Alarmed at a growing international campaign against its use of child labour, Thailand last week vowed to execute anyone causing the death of a child through forcible detention or inhumane treatment. Parents who sell their children into prostitution, a common practice in remote northern provinces, will permanently lose all rights to their offspring. Trade unions in the United States are threatening a boycott of Thai goods unless child labour is wiped out. Earlier this year, Australia raised the issue on a diplomatic level at the United Nations. Laws already exist banning employment below the age of 13, but welfare experts say they are rarely enforced and, in any case, the working age is too low. Police almost never prosecute the powerful owners of factories or sex outlets. It is commonly accepted that low wages from child labour helps to drive Thailand's soaring economic growth, which is expected to reach eight per cent this year. The child employment market exists because of little local employment and the widening prosperity gap between rural and urban dwellers, exacerbated by deteriorating environmental conditions in rice farming districts. A devastating drought since November, believed to be partly a result of deforestation and poor water conservation, came as farmers grappled with a big slump in rice paddy prices. Education authorities fear that three out of every four children reaching the primary school leaving age of 12 in northeast Thailand - an estimated 300,000 pupils - will seek work when their annual holidays start next month. Tens of thousands of others are expected to cross from neighbouring regions, which have been similarly affected. The main flow of children comes from the north-east, the poorest and most economically backward region of Thailand. But ominously, cheaper sources of labour are now appearing across the western and eastern borders. Brothels have recruited hundreds from the Indochina poverty belt of Burma, Cambodia, Vietnam, Laos and southern China, raising fears of a rapid spread of AIDS. There were virtually no AIDS cases there until a few years ago, but the cross-border sex industry is creating a potential epidemic. HEALTH officials have also reported a surge of AIDS cases among Thai schoolchildren, although the government denies that it is widespread. Child Workers in Asia, a crisis group helping child labour victims, believes most young people reach the cities through organised recruitment networks canvassing poor rural communities. ''We have come to know there is a kind of trafficking going on in Bangkok: it's not as if they come on their own, they are trafficked through brokers and agents who are involved in child prostitution and women and drugs from China and Burma. It's a serious industry and it's very hard to trace,'' said Ms Panudda Boonpala, the agency's co-ordinator. A study by the Anti-Slavery Society found that children were being sold for as little as 45 baht (about HK$14) outside Bangkok's Hualampong station, the acknowledged centre of the child labour trade. It reported that children were being sent down mines, employed in dangerous metalworks, in quarries, construction sites, textile and garment factories and assembling toys. A large number are, in effect, prisoners, forced to work after being sold by their parents or lured with false job promises. Girls frequently end up in brothels, where they can fetch four times more than older prostitutes. ''I was told I would be waitressing in restaurants. But when we reached Bangkok I was made to sleep with foreigners in this dirty room, sometimes more than 20 a day. We were made to take [amphetamine] pills so we would stay awake,'' said Mia, who arrived in the city last year. ''They locked me up at first until I repaid the agent fee, but now I just accept this is my fate and I will stay here. Nobody wants to be seen with a prostitute in my village.'' Faced with the threat of trade sanctions, the government implemented a 10,000-baht fine in January for anyone caught buying sex from children. Police promptly arrested a Swedish tourist in the eastern resort of Pattaya last week with a young boy. The Children's Foundation, a charity helping child labour victims, estimates that there are 800,000 children involved in prostitution in Thailand, though this figure is disputed by health authorities. It believes 40 per cent are HIV-positive. But the ready availability of new girls makes it easy to replace them. ''Some foreigners, especially Asians, believe they will be safe from AIDS if they go with younger girls, so the demand for child sex has suddenly shot up. In reality, though, they are just as much at risk,'' said a welfare worker, who declined to be named. The danger of exploitation is even stronger in sweatshops, where children are forced to work 18-hour days with little or no payment. Children freed in police raids have been found chained to the floor in windowless rooms. Most were beaten regularly and lived on a starvation diet. Social workers say parental pressure and unrealistic economic expectations fuelled by Thailand's consumer boom are to blame, together with the collapse of traditional rural values. ''When the children finish primary school, the question to them is what to do if they are too poor to carry on (in) secondary school. If they don't see the benefits of secondary school they will look for work,'' said Ms Panudda. ''It's not that they don't know about the dangers of work, but they would see it as . . . their position. Obviously if they felt that working in their family, on their farm, doesn't bring enough reward, then they will look for a job outside their family.'' There is little hope that the problem will be eradicated until an improvement in education and work prospects removes the need to migrate. Prominent human rights activist, Professor Vitit Muntarbhorn, dismissed the government's latest measures as ineffective, blaming the problem of child labour on a ''social malaise''. ''We have enough laws, but they are rarely implemented,'' he said.