The children at the Bahay Tuluyan street child- ren centre in Malate, Manila's former red light district, studiously ignore a middle-aged, Western male visitor. They look intently at a battered television screen showing cartoon films, while others play a listless game with their backs turned to the stranger. Their indifference, verging on hostility, is not surprising. Most of these children have been working as prostitutes and have encountered Western males in rather different circumstances.
Some five minutes' drive from the centre, cameras are rolling as the actress Kerry Fox makes her way into a seedy hotel in the company of the actor John Hurt. She is cradling a very small baby provided by one of the many Vietnamese boat people in the Philippines who have been recruited to act as extras in a BBC drama being filmed in Manila.
The drama, called Saigon Baby, could be about the illegitimate baby of one of thechildren at the Bahay Tuluyan. In fact, it is set in Bangkok and Saigon, but the authorities there were not prepared to allow the filming of a story dealing with the twin subjects of child prostitution and baby smuggling.
The Philippines, where the fantasy world of the cinema mixes seamlessly with reality, is more open to film-makers; it is also, as it turns out, unwittingly hospitable to sex tourists and locals who use children, most in their early teens but some as young as six years old, for sexual purposes.
The number of child prostitutes is growing by the day. Amihan Abuela, executive secretary of the End Child Prostitution in Asian Tourism organisation, says it is conservatively estimated that there are one million child prostitutes in Asia, of whom some 60,000 are in the Philippines. There are far more in India and Thailand, and growing numbers in Sri Lanka and Taiwan, she says.
It is hard to pin down what made the child-sex trade mushroom in the Philippines, but it seems most likely that it began to grow during the Vietnam war, when American servicemen came to the US bases and resort areas for rest and recreation. They were soon joined by well-organised groups of paedophiles and other overseas sex tourists who would not normally seek children for sex but quickly lost the inhibitions which would have restrained them back home.
Most of the overseas customers come from Australia and Japan, but there are also significant numbers of sex tourists from Britain, the United States and Germany. Nowadays, however, most child abusers are local men whose ignorance leads them to believe that children are less likely to be affected by the HIV virus than adult prostitutes.
It is hard for young girls to resist demands for unprotected sex; they therefore face not only the danger of HIV infection but are also vulnerable to unwanted pregnancy. Abortion is illegal in the largely Roman Catholic Philippines, so those with enough money face the perils of back-street abortionists. Others who have no means of supporting their babies turn to baby smugglers, who always seem to know overseas couples unable to adopt children in their own countries.
"If a child gets pregnant as a result of an exploitative act, it's often very hard to feel affection for the baby, and they have no means to look after it," Miss Abuela says. "The procedure for legal abortion in the Philippines is very tedious, so they figure they might as well get something out of their babies."
This is where middlemen, like the character portrayed by John Hurt in Saigon Baby, step in. He plays Jack, a rather seedy chancer living on his wits in Thailand. The drama explores the morality or otherwise of baby smuggling and the problems of child prostitution. It is a story about a childless, middle-aged British couple, unable to adopt a child through conventional channels, who have finally turned to Jack in a desperate attempt to find a child. Hurt is "completely fascinated" with his character: "I see him with a different morality," he says, brushing aside suggestions that the baby smuggler and procurer of prostitutes is amoral.
The carefully researched and sensitive script, written by Guy Hibbert, portrays the complexity of the situation facing the would-be parents. Kerry Fox's character is eventually sickened by the baby trade, tormented by not knowing enough about the baby's mother, and turns on Jack as the embodiment of all the evil which gives rise to abandoned babies.
He is unrepentant: "You did not come here to adopt a baby - you came to steal one," he tells her coolly. "You're in the business of baby trafficking. ... You have come here like tourist men come here for sex because you can't get what you want at home. And you can get it here because you have the money and these people don't."
"As long as you have desperate people from the West who want babies, you'll have the baby trade," says Josh Golding, the film's producer. "Where do you draw the line? Is it a voluntary decision for girls and women to give up their babies?"
Equally, is it a voluntary decision for any young girl or boy to become a prostitute? Some apologists for child prostitution suggest that there is an element of choice and that people who are not involved have no right to impose their morality on those exercising the choice to sell their bodies.
This view is treated with contempt by those who work with child prostitutes. "There is no such thing as voluntarism for the children," says Nicanor Arriola, the programme director of Bahay Tuluyan. He cites the example of a girl who was sexually abused by her father for three years until she finally ran away from home and found work in a girlie bar, where, almost inevitably, she graduated to the ranks of prostitute. "She had such low esteem of herself that she did not seem able to see any alternative," Mr Arriola explains.
He frequently hears horrific tales of children being raped and beaten. They cannot go to the police for protection because the police have a record of both harassing and even raping child prostitutes. Meanwhile, the circle of degradation widens as more and more children are lured into prostitution by children who have been selling their own bodies but have learned that they can make more money as pimps. Some of them hang around Mr Arriola's centre, trying to lurethe children back into prostitution.
"It's a very traumatic experience," he says. "They use drugs and alcohol to make them immune. They don't want to be abused, but they are trapped'.
In some tourist areas whole communities are dependent on the income of children providing sexual services. Parents either turn a blind eye to how their children earn the money or actively encourage them. "The real cause of the problem is deeper - it's to do with economics, political and social conditions and the fact that demand is very high," says Dolores Alforte, who co-ordinates the End Child Prostitution campaign in the Philippines.
The irony is that although there is no long history of child prostitution in Asia, there are almost certainly more child prostitutes in this region than elsewhere. In the Philippines, explains Amihan Abuela, the people had a far more liberal view of sexuality before the arrival of the Spanish colonisers bringing Christianity. They created a system that helped to breed prostitution as the status of women was reduced, society became more unequal and the balance of power more skewed. "We have learned to be adaptable and to adjust, it's made us more open to exploitation," Miss Abuela says.
Yet child prostitution should not be seen as purely a problem for Asian countries. "Why is there a demand for child sex?" asks Miss Abuela. "Surely it's an indication of serious problems in the countries where the customers come from, which are more affluent and should have more respect for human dignity."
In a shopping mall near the BBC's film set, an extremely large European man is chatting to a slight young boy, wearing a single ear-ring. They disappear into a shoe shop and eventually emerge with the boy holding a parcel. He looks slightlyembarrassed.
His newly found patron does not. They disappear out of the mall together. It is pretty clear what is going on. Both parties will get something out of this transitory liaison, but one is likely to be scarred for life, the other will not. He will hop on his jet plane and return to a faraway country where such things do not happen and he may well be regarded as a model citizen.
`Saigon Baby' is due to be broadcast as part of the BBC's Screen 2 series in the autumn.