According to official figures, more than 20 million Chinese went overseas last year. The record number included students, tourists, businesspeople and tens of thousands of workers. They are building highways and bridges in the United Arab Emirates, Jordan and Yemen, drilling for oil in Sudan and Venezuela, mining iron ore in Peru and Australia and picking fruit in Israel and England. They will soon be planting tobacco and corn in Zimbabwe.

The workers are employed by big, state companies that sign multimillion-dollar contracts for engineering and public works, or they go on their own, legally and illegally, to find work that pays more than they receive at home.

Mass emigration from China began in the 1870s, to Southeast Asia, the Caribbean and northern countries of Latin America, and the west coast of the US. It continued until the communist victory on the mainland in 1949.

The new government sharply restricted migration, but exported labour in teams - in line with the revolutionary ideology of the time - to build sports stadiums, roads, airports and other public works in developing countries in Asia and Africa, many at no charge.

The most famous was the Tanzam railway which opened in 1974, giving land-locked Zambia an outlet to the sea and a rail link to export its copper. In Dar es Salaam, a graveyard the size of a football field holds the bodies of the dozens of Chinese workers who died during its construction.

With the death of Mao Zedong and the new politics of Deng Xiaoping, the strategy changed. The number of aid projects to 'revolutionary friends' fell sharply and the export of labour became a lucrative commercial business.

With the rise of oil prices, the Middle East became the principal destination and Chinese engineering companies were active in the Arabian Gulf, Libya, Jordan, Yemen, Iraq, Egypt and other Arab countries.

The market expanded in the 1990s as Beijing established diplomatic relations with most countries in the world, enabling state companies to obtain work in them. More than 20,000 Chinese went to Israel, replacing Palestinians on building sites and fruit farms.

With the liberalisation of passport restrictions, an increasing number of individual Chinese were able to go abroad in search of work.

These workers have benefited from the low-profile diplomacy adopted by their government since the death of Mao and the replacement of the policy of 'exporting revolution' with one of economic growth. This has helped them avoid association with ideological causes and be neutral in conflicts based on race, religion or colonialism.

'Our policy is to work with the government of a country, whatever it is,' said one retired Chinese diplomat who served in several countries in Africa. 'We differ from western countries, especially Britain, France and the US, which interfere in the government. Our view is that it is up to a country to choose its government and we should not interfere in its internal affairs.'

The events of September 11, 2001 and their aftermath have proved the most serious test of this policy. Beijing aligned itself with the US. While refusing to send troops to join the US-led coalition in Iraq, it co-operated with Washington as never before in fighting Islamic fundamentalists.

'The [Afghan] incident has again demonstrated that terrorism is our common enemy,' President Hu Jintao said last week in Tashkent, Uzbekistan. 'Terrorism, separatism and extremism still pose a serious threat to regional peace and stability.'

The risk of this policy is that the fundamentalists designate China an 'infidel state' and its nationals as targets. According to official figures, there are about 20 million Muslims in China, making them the largest religious minority. They enjoy the same religious liberties allowed by any atheist government.

Several hundred Chinese Muslims have trained with al-Qaeda in Afghanistan, but have not succeeded in persuading its leadership to include China among the 'infidel countries' that are seen as occupiers of Muslim lands.

Fears of fundamentalism are not likely to slow the unprecedented flood of Chinese leaving home, thanks to rising incomes, liberalised passport restrictions and the improved convenience of travel.

It has given foreign countries, especially the most popular destinations - the US, Canada, the European Union, Australia and New Zealand - the dilemma of how to choose between the Chinese they will allow access and those they will refuse.

For example, in Britain there are about 100,000 illegal Chinese working on farms or in factories and restaurants. Most are farmers from the southeast province of Fujian or urban workers from the northeast.

Britain is one of the preferred destinations because it's one of the few countries in the world that doesn't require people to have identity cards. Once an illegal enters the country, he or she should be able to remain undetected unless they are involved in a crime or accident. Most Chinese illegals live in the big cities, but 6,000 were found working on farms last year in King's Lynn, a prosperous town of 60,000 in the east of England.

France is also a popular destination, with an estimated 60,000 illegal Chinese entering each year. Last year Chinese accounted for 4,100 of the 10,500 people refused entry at Charles De Gaulle airport in Paris.

Techniques used for smuggling people are increasingly sophisticated. For example, after he is on board the aircraft bound for Europe, a Chinese is given a fake passport from Thailand or Singapore - countries which do not need visas to enter France's Schengen area - that they use on arrival. This will cost 100,000-200,000 yuan.

A recent scam has been to smuggle children, to exploit a French law that bans the expulsion of those below the age of 18. Last year, French police arrested a couple who had over a three-year period smuggled in 500 Chinese minors, at Euro20,000 (HK$188,772) each.

The snakeheads leave the children in front of courts or police stations and they are handed over to welfare agencies. When they become adults, they can apply for French citizenship - and bring their families with them.