Expert advice received by the Ministry of Agriculture (Maff) as long ago as 1995, warned that an antibiotic resistance gene inserted into a type of GM maize was so powerful that it could degrade an antibiotic in the human gut in 30 minutes.
The antibiotics are used to treat people with diseases such as bronchitis, septicemia, gangrene and life-threatening infections suffered by people with cystic fibrosis and Aids.
The leaked advice, from members of the Government's powerful Advisory Committee on Novel Foods and Processes, warned that the antibiotic resistance genes can mutate.
GM maize is already grown in the US and imported into Britain in foods such as tortilla chips.
The leaked advice has brought calls from environmentalists to ban the import into Britain of all GM food containing antibiotic resistance genes.
The week the Liberal Democrats will take the toughest stand by any political party yet on GM when they publish a policy paper on genetic modification. The party will call for the "swift phasing out of the use of antibiotic marker genes".
"It is completely irresponsible for the Government to allow antibiotics to be used indiscriminately like confetti at a wedding," said Norman Baker, the Liberal Democrat environment spokesman.
The Liberal Democrats will call for genetic engineering companies, such as Monsanto and Novartis, to be legally liable for millions of pounds of compensation if the food turns out to harm people.
However, Novartis has defended its BT-maize, which was one of the first genetically modified products in agriculture, as "completely safe".
"The risk of antibiotic resistance in medical practice is not affected by BT-maize. This conclusion has been reached by all expert committees who have studied this question," said a spokesman.
But a letter written to Maff in 1995 by a scientist on the Advisory Committee on Novel Foods and Processes warned that the maize could produce resistance to several key antibiotics.
"I have been reliably informed that the production of this enzyme would result in resistance not only to ampicillin, but also to the other penicillins active against gram negative bacteria, namely ampicillin, amoxycillin, piperacillin, mexlocillin, azlocillin, micillinam, carbenicillin and ticarcillin," the letter says. "This gene is in [an] active state of evolution and may undergo mutation."
Another letter from a scientific adviser to the Ministry of Agriculture in 1996 states that the antibiotic resistance marker gene could, in the gut of a farm animal or human, "be sufficient to degrade the normal therapeutic dose of ampicillin in about 30 minutes".
Doctors use these penicillins to treat salmonella, meningitis, bronchitis and infections which are life-threatening to cystic fibrosis and Aids sufferers. They also save the lives of people suffering from endocarditis, an inflammation of the lining of the heart.
"Food containing these dangerous antibiotic resistance genes are coming into the country. If other countries are banning it on health grounds, why aren't we?" said Adrian Bebb, of Friends of the Earth. "This just shows how the Government in this country is putting business interests before public health interests."Reuse content