Confidential Chinese government documents show that the incidence of cancer and related diseases in areas around the test site is up to 39 per cent higher than in the rest of China. Among the more common diseases are tumours, leukaemia and birth defects such as cleft palates.
The revelations come as Tony Blair, the Prime Minister, flies to China for a six-day visit starting tomorrow. He will discuss nuclear testing and human rights issues with Zhu Rongji, the Chinese Premier.
Information gathered in western China by a Channel 4 Dispatches documentary team has revealed a disturbing climate in which doctors with few resources struggle to treat the diseases. Many victims receive little if any help.
The evidence also underlines an ongoing racial conflict between the Turkic Uighurs who populate the area and the Han Chinese of the east. In recent years the area has seen increasing disputes between the groups and a growing independence movement similar to that in neighbouring Tibet.
The team spent six weeks working undercover and using hidden cameras in the far west of China. They were helped by a Turkish doctor who had spent 10 years working in the region and used his medical contacts to obtain much of the documentation.
The evidence was gathered in the supposedly semi- autonomous province of Xinjiang, home to the legendary Silk Route towns of Kashgar, Turpan and Urumqi. It is here at Lop Nur on the edge of the remote Taklimakan desert that China has pursued a nuclear testing programme over the past 30 years.
The country tested its first nuclear device in 1964 and its most recent on 30 July 1996. It only started testing underground in 1980.
In all it has tested 47 nuclear devices - some more than 300 times more powerful than the Hiroshima bomb. Fall-out from the nuclear tests has even been detected in Britain.
Of all the nuclear powers, the testing programme of the Chinese is perhaps the most secretive. Groups such as the Campaign for Nuclear Disarmament (CND) say much collected data are based on estimates.
"Very often the data relating to the Chinese tests simply says `estimate' or `not available'," a CND spokesman said yesterday.
The research found children and young people with horrific birth deformities and diseases. Cases such as an 18-year-old man who has not been able to walk since he was six because of a degenerative disease are common.
Another woman told how her 17-year-old daughter suffered from cracked bones and a wasting of her flesh, similarly diagnosed as being caused by a degenerative disease.
Dr Laura Watson, who helped to gather the evidence and met many victims, said: "It is well known that radiation can lead to many cancers and congenital abnormalities. You get a big increase in the incidence of ordinary diseases.
"Not only can it lead to solid diseases, like cancer of the liver or lungs, but it can also cause leukaemia."
While the researchers were unable to quantify the precise number of victims, confidential official documents obtained from medical sources in Xinjiang reveal that since the mid-1970s there has been a steep rise in the incidence of such diseases in Xinjiang compared with the rest of China. By 1990 the cancer rates in towns around the test site were more than 35 per cent higher than the national average.
The documents reveal that the specific types of cancer that have been increasing - malignant lymphomas, lung cancer and leukaemia - are those associated with radioactivity. Dr Watson said she thought the findings were "absolutely astonishing".
While the Chinese authorities may have acknowledged the increase in cancer victims, they deny that it has anything to do with the nuclear testing programme.
But many doctors working in the province are convinced of the link. One male doctor, who asked to remain anonymous, said: "Basically cancer is everywhere in Xinjiang ... the increase has been dramatic over the past 20 years or so. There is a lot from the south."
Another doctor added: "The nuclear explosions have increased air and water pollution. We can't do any research into it, it's not allowed."
One doctor said that 10 years ago, during a period of testing, a staggering 8 out of 10 children he was seeing were suffering from cleft palates. "Nobody has ever said it but we think the nuclear pollution causes them," he said.
Not only are the doctors facing an official refusal to admit the problem, they are also having to try to treat the victims with inadequate facilities.
Yet another pleaded with the researchers for help to deal with the problem. "We can't do anymore. We need more resources."
Dispatches, Channel 4, 8pm tomorrow.Reuse content