Trading standards officers from around the country have been carrying out random tests on food to see if labelling laws, which state that GM ingredients should be identified on the packet, are being followed.
About a third of tests carried out for trading standards departments revealed food containing unidentified GM ingredi- ents. Many apparently GM-free snacks and meals, particularly ones sold as health foods, were found with GM ingredients.
The Independent on Sunday is campaigning for clear, accurate labelling on all GM foods, and the results of this survey have prompted food groups and MPs to call for labelling and tougher testing. "Consumers have been promised that food containing GM ingredients will be labelled, but here is evidence that companies are not following the law," said Sue Dibb of the Food Commission. "Companies have no excuse for this."
In East Sussex, council tests on food containing maize and soya found two brands of toffee-covered popcorn contained GM soya in the ingredients although the labels suggested that the snacks were "GM-free".
At Denbigh in North Wales, soya mince sold with no GM label was found to contain engineered soya.
In Oxfordshire, trading standards officers took 20 samples of products containing conventional maize and soya. They found that four out of 10 "GM-free" soya products, including bacon-flavour soya chips, soya-bean curd and textured soya protein, had genetically modified soya beans. Their tests also showed that three out of 10 randomly tested foods containing maize, which did not include a GM label, had GM ingredients. One was a brand of tortilla chips containing maize grown in the United States.
Norman Baker, Liberal Democrat environment spokesman, said: "We can have no confidence in the labelling of GM food. The Government really must act to ensure that labelling is based on what goes in the food so the consumers can have confidence in what they are eating."
In Britain, under European Union law, all foods containing GM ingredients are supposed to be labelled. But, because the Government has not yet finalised its own labelling regulations, there are no penalties in force for companies that break the law.
"We believe in consumers exercising an informed choice and consumers should have accurate information and the ability to exercise that choice," said Alan Street, chief executive of the Institute of Trading Standards.
The tests were carried out for trading standards departments by public laboratories, including the Central Scientific Laboratory run by the Ministry of Agriculture, which have devised a way of detecting genetically modified DNA.