Revealed: Shocking new evidence of the dangers of GM crops

More than two-thirds of conventional crops in the United States are now contaminated with genetically modified material - dooming organic agriculture and posing a severe future risk to health - a new report concludes.

More than two-thirds of conventional crops in the United States are now contaminated with genetically modified material - dooming organic agriculture and posing a severe future risk to health - a new report concludes.

The report - which comes as ministers are on the verge of approving the planting of Britain's first GM crop, maize - concludes that traditional varieties of seed are "pervasively contaminated" by genetically engineered DNA. The US biotech industry says it is "not surprised" by the findings.

Because of the contamination, the report says, farmers unwittingly plant billions of GM seeds a year, spreading genetic modification throughout US agriculture. This would be likely to lead to danger to health with the next generation of GM crops, bred to produce pharmaceuticals and industrial chemicals - delivering "drug-laced cornflakes" to the breakfast table.

The report comes at the worst possible time for the Government, which is trying to overcome strong resistance from the Scottish and Welsh administrations to GM maize.

The House of Commons Environmental Audit Committee drew attention to the problem in North America in a report published on Friday, and said the Government had not paid enough attention to it. The MPs concluded: "No decision to proceed with the commercial growing of GM crops [in Britain] should be made until thorough research into the experience with GM crops in North America has been completed and published". It would be "irresponsible" for ministers to give the green light to the maize without further tests.

Peter Ainsworth, the committee chairman, accuses the Cabinet of "great discourtesy" to Parliament by making its decision on the maize last Thursday, the day before the report came out, and plans to raise the issue with the Speaker of the House.

This week's statement by Margaret Beckett, Secretary of State for the Environment, is expected to fall short of authorising immediate planting of the maize, and provide only a muted endorsement for the technology. She will make it clear that the Government wants the GM industry to compensate farmers whose crops are contaminated. This could make cultivation uncommercial. The US study will increase the pressure on her to be tough.

Under the auspices of the green-tinged Union of Concerned Scientists, two separate independent laboratories tested supposedly non-GM seeds "representing a substantial proportion of the traditional seed supply" for maize, soya and oilseed rape, the three crops whose modified equivalents are grown widely in the United States.

The test found that at "the most conservative expression", half the maize and soyabeans and 83 per cent of the oilseed rape were contaminated with GM genes - just eight years after the modified varieties were first cultivated on a large scale in the US.

The degree of contamination is thought to be at a relatively low level of about 0.5 to 1 per cent. The reports says that "contamination ... is endemic to the system". It adds: "Heedlessly allowing the contamination of traditional plant varieties with genetically engineered sequences amounts to a huge wager on our ability to understand a complicated technology that manipulates life at the most elemental level." There could be "serious risks to health" if drugs and industrial chemicals from the next generation of GM crops got into food.

Lisa Dry, of the US Biotechnology Industry Association, said that the industry was "not surprised by this report, knowing that pollen travels and commodity grains might co-mingle at various places".