If you cross the Triads or the Snakeheads, they don't care how you pay back the money. They might torture you while your family is forced to listen on the telephone. Or you might be sold into prostitution to pay off a debt that never diminishes.
In Britain, Chinese Triad gangs operate as semi-autonomous branches of the Triad organised crime groups in Hong Kong and the US. Together with organised criminal gangs from eastern Europe notorious for drug trafficking and extortion, British Triads are increasingly turning to the slave trade as an untapped source of finance.
The Snakeheads, the Chinese crime groups specialising in human trafficking, control most of the business. But there is an increasing amount of overlap between them and the Triads in the battle to make money.
About 80,000 illegal immigrants were smuggled by various means and routes into Britain last year and for the Triads and organised crime gangs, the human trade represents a massive profit each year.
The British government's response to this illegal trade was to post a network of 12 officers from the Immigration Service at key points along established smuggling routes in eastern Europe and Asia.
The officials began working alongside peacekeeping forces - who stress it is not their role to check the identification papers of suspected illegal immigrants - in places such as Kosovo and Bosnia, other Balkan countries and Poland last year and collect data on smuggling routes and the gangs sending thousands of illegal immigrants across Europe and into Britain.
Officials from the Home Office already work with airport liaison staff and Customs officers to block overland and sea routes into Britain which, despite the deaths of 58 Chinese immigrants who suffocated in the back of a baking hot lorry on a cross-Channel ferry last year, still represents a desirable economic destination.
Increasingly, Triad gangs involved in the multi-million pound business of human trafficking, the sex trade and organised crime, are extending their networks throughout the British regions where detection by the police is less likely, but the profits are just as high as in London.
The shift is partly due to the extent to which criminal gangs from eastern Europe have infiltrated, and in some places dislodged, the traditional criminal hierarchy in London's Soho district. Long established as the hub of the Chinese community, the area is now seeing more "red light" establishments run by Russian gangs than Chinese gangs.
The Home Office recently highlighted a survey suggesting that up to 70 per cent of sauna and massage parlours in Soho were being operated by Albanian and Kosovar gangs and the National Criminal Intelligence Service (NCIS) says the number of Thai and Philippines women being sold into prostitution by Chinese gangs in London is declining.
Instead, the women are being sold as prostitutes on false visas to other countries or the Triad gangs are selling them into previously untapped areas for organised crime in Britain.
So, as the Triads move into places such as Manchester and Glasgow, Lithuanian, Polish and Russian woman, some of whom are duped into prostitution with the promise of a place to study English, have displaced the Thai prostitutes in London.
Yet for all the obvious disadvantages of travelling illegally across Europe, up to 400 Chinese men attempt to enter Britain illegally each week. In Soho employment is increasingly hard to come by as the population increases. And since many immigrants come from China's Fujian province and London's Chinese community is largely from Hong Kong, cultural differences can be hard to overcome, making assimilation difficult.
Even when the Chinese reach London, the threat to their lives is undiminished. If they fall behind on their payments of the smuggling fee, often up to £20,000 sterling, the Snakeheads's representatives might kidnap and torture them so that their families in China will pay the rest of the money.
A recent investigation by the Observer into human trafficking and the sex trade in Britain highlighted the attraction for criminal gangs and Triads. A police source was quoted as saying: "If you get caught smuggling cocaine, you're looking at 20 years. If you smuggle women, the profits can be just as high and if you get caught the only thing you're looking at is living off immoral earnings. If you're a criminal, the choice about which to go for is pretty simple."