"It's the new Costa del Crime,"

he says, thanks to the numbers of Brits fleeing the law at home for lives of lucrative, beachfront liberty in Thailand. "You see them all there in their singlets and tattoos. It's a perfect place for them. What the Thais must think of British people I have no idea."

Pattaya gained its reputation as a place where sex was for sale during the Vietnam war when US servicemen would come to Thailand for "rest and rehabilitation". The trade continued after the war, with western tourists filling the vacuum. Now everything sexual is available. Young women dressed as schoolgirls beckon customers into Classroom-A-Go-Go (motto: "study hard") and young men in white T-shirts and shorts follow suit at Narcissus. There are women dressed as secretaries at a bar called the Office Girls and encased in silver dresses at another, Crystal Girls. "What makes it attractive for someone on the run is that it is very easy to pick up bogus ID, it's very cheap to live and you can get yourself fixed up with a Thai woman very easily," says Sweeney.

The lid was lifted on the British expat underworld in Pattaya during a murder trial at the Old Bailey in December. Matthew O'Connor, a London taxi driver and martial-arts expert who co-managed the Camden club Barzaar, was charged with the 1997 killing of Ronald Hinkson outside his club. O'Connor, who fled the country with a false passport immediately after the killing, was tracked down to Thailand four years later and spent two years in jail there fighting extradition. He was acquitted of the murder after he told the jury that he had not been involved and had only disappeared because he believed the dead man's friends were after him.

O'Connor, like many on the run, had managed to create a new world for himself in Pattaya, complete with a Thai partner with whom he had a son. He might have spent the rest of his life there, untroubled by the British police, had it not been for another Pattaya expat, Ian Muirhead. A small, nervy man, Muirhead had been in jail for various offences in Britain and the US before he ended up enjoying the benefits of Thailand. There he set himself up as a cigarette smuggler and importer of fake Gucci and Louis Vuitton accessories. He also made a speciality of supplying fake visas and travel documents, thus facilitating illegal immigration scams.

Muirhead's modus operandi, typical of the counterfeit trade from Thailand, was to purchase fake fancy goods at a fraction of the price of the genuine article, ship them back to London and have them sold off by associates working in the London markets. He was not making a fortune - he reckoned between £2,000 and £4,000 per monthly trip - but combined with the phoney visa business, it provided a comfortable life. He was arrested in England in 2002 after trying to pull off one trip too many. In exchange for a £21,000 reward, he divulged the new identity and whereabouts of O'Connor, then operating under the name of Roy Cann. He is now living at a secret location.

O'Connor, who had used Muirhead to collect money for him from London, had also found the counterfeit goods trade allowed him a comfortable life in Thailand. Like Muirhead, he traded in replica football shirts, buying them for £3 and selling them for £15. The fact that Thailand is one of the world centres of counterfeit production provides expat criminals with a wonderful way of making money relatively free from risks. If they have legal problems, the police are very bribable.

The old Costa del Crime in the south of Spain was where villains took advantage of the collapse in 1978 of the extradition agreement between Spain and the UK. For a while in the 1980s, up to 100 major British criminals enjoyed their San Miguels without fear of a hand on the collar of their Hawaiian shirts (the door to Spain was closed in 1985 with a new extradition accord, although it didn't apply to those who were there already). The old Costa del Crime provided a haven with full access to the staples of the expat Brit: televised football, beer and breakfast. Pattaya can offer all of these - along with a young female population who show an unfailing attraction to well-off, middle-aged Brits in shorts and sandals.

So is Pattaya really the new Costa del Crime? "Not at all; it's more like Blackpool," says one expat Londoner who now owns a bar just up the road from the Dog's Bollocks, where Muirhead and his pals hung out. The staff and customers there were more reticent: a journalist exploring this theme around the time of the last World Cup got, I was told, "a smack in the mouth".

"It's really very relaxed," says the Londoner. "There are a few ex-cons here but I don't know of anyone on the run - apart from one guy who's now gone to the Philippines [which has no extradition treaty with Britain]. You get all kinds here: your golfing fraternity and just normal people." Oddly, no one in this supposedly family-friendly golfing idyll wants to talk on the record. To an observer, indeed, Pattaya is much more identifiable as the home of "beer bars" where a "bar fine" is paid to take a woman off for sex, or go-go bars where "lady drinks" are bought for the dancers, who are also available for sex for as little as £10. A Brit on the run can, for very little investment, find himself a woman, a place to stay, a new identity and, with the right connections, a way of scamming enough money to stay for ever.

Of course, there are plenty of expats who have nothing to do with crime and who are attracted by the sun and cheap property. Around £30,000 will buy a very comfortable apartment near the beach, and rents are minimal - 650,000 British tourists visit Pattaya every year. One legitimate English businessman who has been in Pattaya for a decade says he has seen the town grow by 10% a year since then. There were some problems on the criminal front, he says, but mainly with people who overstayed their visas.

There have, however, certainly been no shortage of crime stories involving Britons in the town. Last month, Bernard Le Court, a 52-year-old chef from Liverpool who moved to Thailand six years ago to open a restaurant, had his throat cut in Pattaya. A local taxi driver was arrested after the body was found in bushes near Pluta Luang, 22 miles south of the town. He was said to have heavy gambling debts and to have robbed Le Court of his camera equipment and money. He could face the death penalty if convicted.

The lively local paper Pattaya Today, one of three local English-language publications, provides a round-up of the criminal happenings complete with graphic photos: Thai police make a speciality of posing beside the bodies of murder victims. In one week last month it was carrying reports of a Briton, Alexander Downey, caught with three packs of "ice" (pure amphetamines), and a report that noted that "the Brit's landlady said she believed he had made some enemies in Pattaya and they had decided to put an end to his nefarious activities". Another report told of a "Swiss guy found expired in condo - possibly hit with hard object".

It is not only British criminals who are attracted to Thailand; while the British and Australians are the most involved in the counterfeit business, some sex trade and drugs, Russians are involved in prostitution and West Africans in drugs and diamonds. Down on the front, one 20-year-old Thai businessman offering fake YSL suits says that Englishmen have a bad reputation locally: "They get very drunk and sometimes you get a group of them and they take a woman and they don't want to pay her and they rape her. There are Germans, too, but the English are the worst." Pat, a 27-year-old Thai bar-girl, says the English are the best and the worst customers. What does she mean? "They do like to get very drunk."

Unlike Patong, Thailand's other main hangout for British expats and tourists, Pattaya was not affected by the Boxing Day tsunami. There is little doubt, however, that the catastrophe in the region may have provided some people with a perfect way of disappearing. There are many apocryphal tales in Pattaya about British criminals who got new identities after claiming that their passports had been washed away in the waves. Even if they can't secure a phoney identity in Thailand, a taxi ride from Pattaya takes you over the border into Cambodia where it is even easier to disappear. Last summer, a bogus passport ring was busted in Bangkok with false ID from New Zealand, France, Belgium and Spain being sold for as little as €1,500 (£1,000 each). There are services available, too, for criminals who want to stay in Thailand but who do not want the risk and bother of travelling abroad to get their visa renewed. For 3,200 baht (£42) for a tourist visa or 7,500 baht (£100) for a three month non-immigrant visa, someone will leave the country on your behalf and return with the necessary renewal stamp.

There are currently 41 Britons in jail in Thailand, according to Prisoners Abroad, mostly on drugs charges; some are serving sentences of 49 or even 99 years, their only faint hope a royal pardon. The jail where they are housed, the Bang Kwang or "Bangkok Hilton", has now become so notorious that visiting a detained Brit has been added to the list of things to do for backpackers in the area. In a recent book called Guns, Girls, Gambling, Ganja, three Thai academics from Chulalongkorn University in Bangkok wrote that "Thailand has acquired an international reputation as a country where illegal businesses can flourish because of poor law enforcement. This is bad for Thailand's international reputation." It is, however, good for a Brit on the run.