The exiled paedophiles were trafficking boys from other countries; running legitimate gay brothels and selling under-aged boys "under the counter"; they had branched out into the production of child pornography. And they had killed some of them. One boy had simply been shot through the head, Terry said: he had been causing trouble and had been executed in front of several pae dophiles. Another, he believed, had been thrown into one of the canals. But the one about whom he spoke the most was a boy who had been tortured and killed in the most painful fashion in the course of producing a pornographic video.

Terry said he had seen most of the video himself and had vomited before he could reach the end. The few detectives who specialise in the investigation of child abuse invariably say the same thing about "snuff" movies: they have often heard of them, sometimes pursued them but never found one. The videos remain one of the great unsolved mysteries of the burgeoning underworld of international sexual exploitation.

Twice told tale

Terry's account was so hideous as to invite disbelief. It was clearly possible that he was inventing the story in an attempt to curry favour with the detectives as they turned over Bristol's paedophile subculture. And yet the detectives discovered that the allegation had been made before.

Not just once but repeatedly, evidence had come to the attention of police in England and the Netherlands, that, for pleasure and profit, some of the exiled paedophiles in Amsterdam had mur dered boys in front of the camera. Some of the evidence had been pursued. Some of it had been ignored. None of it had led to a murder charge. For a short while, the Bristol detectives thought they might be able to make progress in tracking down the truth; but when two of them flew to Amsterdam in the autumn of 1998 to pass on their information to Dutch officers, they hit a wall.

Terry had described the flat in Amsterdam where he had seen the video; he had named the owner of the flat who was, by implication, also owner of the video; he had provided the name of the man who carried out the killing; he had described events on the video in detail; he had provided the approximate age and the first name of the dead boy.

Dutch police said it was not enough: without the full name of a victim, they would not begin an investigation. Having fought their way through the swamp of inertia which surrounds British policing and prosecution of child abuse, the Bristol detectives had now hit the deeper swamp of virtual paralysis that afflicts its international policing. Within their own jurisdictions, there are now specialist paedophilia detectives - for example, in London and Amsterdam - who will work relentlessly to lock up predatory child abusers.

But when they try to move abroad, the potentially powerful machine starts to misfire. The result is that there is now a flourishing underground trade in boys who are being exported from the economic chaos of eastern Europe, as well as from the streets of London, to be put to work in the sex industry of western Europe. And no effective police operation to deal with it.

Predatory paedophiles cross whatever borders they like in order to pursue their obsessions; the police who might follow them are almost always trapped within their own narrow jurisdictions, partly by differences in law and procedure, partly because they lack the manpower and money to work internationally. There is an exception to this rule of parochialism, in the highly funded war against drugs, but in the perverse world of modern policing, the trafficking, rape and alleged murder of children has a far lower priority.

We have uncovered an international paedophile ring whose roots spring from Amsterdam, where, in the late 1980s, a group of British paedophiles set up a colony, exploiting the freedom of the city's gay community as cover to make a business of their fantasies.

Legal front

One of the first to do so was Alan Williams, the "Welsh Witch", who already had a vicious history of abusing boys in south Wales. Williams arrived in Amsterdam in 1988, aged 21, and soon set himself up as the manager of a gay brothel called Boys Club 21 at 21 Spuistraat, near the central station. Across the road at number 44, another British paedophile, a chubby Londoner named Warwick Spinks, then aged 25, was running a similar club called the Gay Palace. Both clubs had a legal business, running a bar and offering the services of adult male prostitutes.

But Williams and Spinks had much crueller interests. Williams had fled to the Netherlands after being convicted in Britain of indecent assaults on boys. In Amsterdam, he boasted of the day in south Wales when he had seen a 10-year-old boy on his bike, grabbed him, raped him, and, when he cried, strangled him. From Boys Clubs 21, he organised the importing of boys from Cardiff and London, inflicting intense violence on any who defied him.

Spinks had been running a mail order pornography business from Brighton, before he moved to Amsterdam, where he pioneered the trafficking of boys as young as 10 - first, from the streets of London, and, after the collapse of the Soviet Union, from the poverty of eastern Europe. Having brought them to Amsterdam, he used these "chickens" himself, sold them into the brothels or through escort agencies and put them in front of the camera. Some resisted, some ran away, but most were made to comply through the removal of their passports and doses of drugs and violence.

By 1990, these two clubs on Spuistraat, together with Boys for Men, De Boys, the Blue Boy and the Why Not, had become the busiest watering holes in the international paedophile jungle. Dutch police estimated there were 250 paedophiles involved in the production of child pornography in Amsterdam with an unknown floating population of child sex tourists from all over the world - and it was the British who formed the hard core consumers: Stephen Smith, who had helped to found the Paedophile Information Exchange, fled there when police in England prosecuted the organisation; Russell Tricker, now 58, a former private school teacher who was convicted of child sex offences in the UK, used his job as a coach driver to ferry suitable boys from London; John Broomhall opened a porn shop on Spuistraat and was caught with more than 1,000 copies of videos of under-aged boys; Mark Enfield, now 41, sold a video of himself abusing a drugged boy.

Alan Williams introduced two paedophile friends from Wales, John Gay and Lee Tucker, both of whom were to become central targets for Bristol detectives. The two men found they could sell Welsh boys into the clubs on Spuistraat and then make more money by investing in child pornography. They bought video equipment, set up TAG Films, and visited Amsterdam regularly to make films, which they sold through distributors in the US and Germany. At the time, Dutch law punished production of child pornography with a maximum sentence of only three months.

By October 1990, detectives on the old obscene publications squad at Scotland Yard were picking up worrying signals. An informant told them that someone called Alan Williams was trafficking boys into Amsterdam and that Williams had asked him to smuggle a child porn video back into the UK. Another informant told how he had smuggled a dozen tapes in the opposite direction: they had been produced, he believed, in north London, equipped with a bondage room for boys. He had delivered the tapes in Amsterdam to "Alan from Cardiff" at Boys Club 21. The informant said he had visited the Gay Palace across the road, where he watched videos of boys in bondage, aged 11 to 14, being buggered by masked men.

Soon, other informants were offering more detail. One man said he had seen Warwick Spinks selling a special video for £4,000. It showed a boy whom he thought was only eight or nine being sexually abused and tortured by two men. But the most startling allegations came from a gay man, "Frank", who had gone to Amsterdam in July 1990 and found himself caught up in this paedophile underworld. In 1993, he spoke to the same officers at Scotland Yard.

Frank told police that Warwick Spinks had invited him to come on a trip to the Canaries, where he had suggested Frank should help him sell videos and showed him a sample. Frank said he watched in growing horror as the video played out a murder - a boy who seemed to be no older than 12 was beaten and attacked with needles, before being castrated and cut open with a knife. The video seemed to have been shot in a barn, and detectives later learned that Williams and his friends had been talking about making a video in a barn that belonged to a German from one of the Spuistraat clubs.

Scotland Yard was in a difficult position: the informants were British and so was Spinks, who by this time had left Amsterdam and was living in Hastings, East Sussex. But everything else in the story was scattered round Europe. After long negotiations within Scotland Yard and with their counterparts in the Netherlands, the detectives set up Operation Framework, and, as the Guardian reported in 1997, they recruited an undercover officer to pose as a child abuser and befriend Warwick Spinks in England.

In a series of meetings, Spinks described how he picked up boys in Dresden, in Bratislava in the Czech Republic, and in Poland, where, he claimed, they cost only 10p. The undercover officer asked Spinks if he could get him a sado-masochistic video featuring boys as young as 10, and Spinks replied that he knew people in Amsterdam who could: "I know, well I knew, some people who were involved in making snuff movies and how they did it was, they only sold them in limited editions, made 10 copies or something, 10 very rich customers in America, who paid $5,000 each or something like that".

Spinks divulged no more about the video and failed to produce a copy of it. Without more evidence, Scotland Yard could not justify the expense of keeping the undercover officer or of sending officers to Amsterdam, where, in any event, they lacked police powers. They arrested Spinks in Hastings and charged him with adbucting and raping two homeless boys from the streets of London and selling one of them into a Spuistraat brothel. He was jailed for five years. But the allegation of murder would not go away. As the Guardian reported in 1997, another gay man, Edward, claimed to have seen five Amsterdam videos, each featuring the sexual torture and death of a boy. Dutch police investigated and said they could find no evidence.

Now, Terry had offered the Bristol detectives more evidence about life on Spuistraat. He explained how John Gay and Lee Tucker set themselves up as video pornographers, first taking a group of boys to an isolated farmhouse in France, and then making visits to Amsterdam to film with the boys there. And dealing with snuff movies he told how, in 1989, he had been alone in a flat which belonged to one of the key figures in the Amsterdam paedophile scene, whom he named; he had found a video and watched as it played out a murder - a boy was beaten before being castrated and cut open with a knife.

At first sight, Terry might have been describing the video Frank saw but its details differ: Frank described a video shot in a barn; Terry says his was shot in a flat. Frank described the abuse and murder of one boy; Terry says there was a second boy, who was also being abused and who was alive at the point he turned off the tape. And yet, the overlap is striking: the specific nature of the violence is identical; and Terry names the man who actually committed the killing - he is the same German whose barn was allegedly picked as a porn studio by the child porngraphers.

Terry, Frank, Edward and Spinks certainly mixed with the paedophile colony in Amsterdam in 1989/90 and all four separately claim at least one boy was killed on video. Spinks told the undercover officer that a German boy was killed; Frank says Spinks once hinted to him that a German boy named Manny had been murdered; we have confirmed from talking to boys who worked in Spuistraat at the time that a boy of that name and nationality, then 14, did disappear. Terry, however, says he thinks the victim of the video which he saw was Dutch, named Marco and probably 16.

Currying favour

At one end of the scale of possibility, every one of these men may be lying in an attempt to score favours with the police or to cause trouble for others on the Amsterdam scene, and certainly it was not unusual for boys to disappear from Spuistraat simply because they had had enough of being exploited.

At the other end of the scale, the truth is that one or more boys was killed in a snuff movie - and the murderers have got away with it.

The Bristol detectives can get no further. The Dutch say they will not investigate, and Avon and Somerset police have neither the funds nor the legal power to run their own inquiry in the Netherlands.

There have been successful paedophilia operations between British and European police. Scotland Yard detectives recently have twice arrested wanted men and extradited them to the Netherlands for trial on child sex offences. Within their borders, the Dutch paedophilia unit have arrested several of the key British paedophiles, and, since January 1996, the Netherlands has introduced a tougher law, which threatens up to six years for production of child pornography. The clubs on Spuistraat are no longer the paedophile playground they were. But the wider picture is of police trapped within their borders with the result that the European trade in boys for sexual exploitation has been allowed to grow without restraint.

A couple of years ago, I sat in the Blue Boy club on Spuistraat, amid the dry ice and the boys in thongs, and flicked through the catalogue on the bar, offering "truly the best boys in town", and watched a Japanese businessman make his purchase. In search of their origins, I went to Berlin, to the Bahnhof Am Zoo, where the trains arrive from all over eastern Europe, bringing the destitute in search of a dream. A specialist social worker there, Wolfgang Werner, told me there were some 700 east European boys, aged from 11 to 17, who had ended up in the sex industry in Berlin. But, to his knowledge, many hundreds of others had been taken off on a kind of underground railroad which fanned out to Zurich and Hamburg and Frankfurt, and, most of all, to Rotterdam and Amsterdam.

Werner told me, for example, about the Romanian boys who had been sold by their parents to a wandering Polish criminal, who had paid cash for some and a bottle of vodka for another, before putting them on to the streets of Berlin.

I followed the trail of two men, Peter Goetjes and Lutz Edelman, identified as traffickers in the Berlin press. Eventually, I spoke to a friend of theirs, who said that, of course, they had been trafficking. They must have sold 150 between them, before Goetjes was caught on the Polish border in the summer of 1992 with a boy in his boot. Goetjes was charged with smuggling, released on bail and then drove away and never came back for his trial. About that time, he and Edelman stopped trafficking, not so much because of Goetjes's arrest but because they had been told some of the boys were being used in snuff movies. Plenty of others carried on.

Unheeded warning

In May 1995, Bjorn Eriksson, then president of Interpol and chief of the Swedish police, told a conference on cross-border crime that organised paedophile networks were operating across European frontiers and as many as 30,000 paedophiles were believed to be linked to organisations or publications throughout Europe. His warning went unheeded.

In the late 1990s, trafficking of boys from Berlin to the Netherlands hit the north European press when police belatedly tried to find out what had happened to a 12-year-old Berliner, Manuel Schadwald, who went missing in July 1993. The Berlin police had simply listed him as a runaway. By 1997, however, Dutch journalists had dug out a history of sightings which suggested he had been put to work in a brothel in Rotterdam, run by a German, Lothar Glandorf, now 36. After ignoring complaints for 18 months, Rotterdam police targeted him and found he had been selling hundreds of boys. Of those they could trace, nearly half were under 16.

The Guardian has obtained an extraordinary report which was produced by Rotterdam police. It captures some of the ruthlessness of life in the city's boy brothels: "Even if Glandorf knew the perversions of a customer, he would still send a boy to a customer who had a preference for sado-masochism."

In the midst of all this, Rotterdam police were looking for Manuel Schadwald. Their report reveals three boys had run away from Glandorf's world and reported sighting the missing Berliner. Police logs leaked to a Dutch TV programme, Netwerk, reveal that one night, three Rotterdam surveillance officers saw Glandorf with a boy all three believed to be Manuel Schadwald but they failed to rescue him: they were reluctant to break cover for fear of jeopardising their operation. With the Dutch and German press baying for action, police in the two countries set about trying to find him - four years after his disappearance. They failed.

The same cross-border weakness persists. Investigating Glandorf, the Rotterdam police found that British paedophiles were routinely using his brothels, but they never sent a copy of their report to Scotland Yard. Glandorf had little fear of international policing. When a senior Dutch civil servant phoned him from Poland to say he was bringing back a boy, police phone taps recorded Glandorf saying: "When you get to the bridge at the border, let him out so he can go on foot so they can't catch you." That was all it took.

Within their borders, the Dutch did finally jail Glandorf for five and a half years, and yet the Amsterdam paedophiles remain relaxed. Some have resettled in Prague, where the law is lax. The trains still pull into the Bahnhof Am Zoo with their consignments of vulnerable children. The international boy business is alive and well, and, quite possibly, getting away with murder.

 Identities of all police informants have been disguised.