Science policy researchers argued a week ago that GM foods should be subject to the same rigorous tests as pharmaceutical products.

They wrote in the journal Nature that the principle of "substantial equivalence", by which GM foods are assumed to be safe if they are chemically similar to their natural counterparts was "misguided" and unscientific.

Listen to the debate Dr Erik Millstone and Dr Peter Kearns had when the original Nature commentary was published

Erik Millstone, from the University of Sussex, Brighton, public health expert Eric Brunner, from University College London, and Sue Mayer, from the pressure group GeneWatch UK, said the principle was "a commercial and political judgement" that benefited manufacturers rather than consumers.

The reaction to their comments has been fast and furious with the latest edition of Nature carrying three hard-hitting replies.

Molecular biologist Anthony Trewavas, from the University of Edinburgh, and plant scientist Chris Leaver from the University of Oxford, accused the three authors of using "ill-informed logic" to obstruct the acceptance of new technology.

They wrote: "Their arguments are a distraction from the task of developing a sustainable and environmentally friendly agriculture, which combines the best of conventional plant breeding approaches with the new technologies."

If their advice was followed, said Trewavas and Leaver, "we would be drowning in toxicity tests".

Derek Burke, former chairman of the UK advisory committee on novel foods and processes, said data not cited by the three researchers had demonstrated GM soya beans were as safe as conventional soya beans. He called their arguments outdated, misleading and inaccurate.

He said their suggestion that an international conspiracy was trying to foist GM foods on a gullible public was "beyond belief", and wondered how such a "mish-mash of old hat sociology and poor science" had got published in Nature.

Peter Kearns, from the Organisation for Economic Co-operation and Development in Paris and Paul Mayers, from Health Canada in Ottawa, Ontario, who helped develop the idea of substantial equivalence, denied that the concept was created as an excuse for not requiring biochemical or toxicological tests.

They pointed out that it was devised before any new GM foods came on to the market by experts who spent more than two years discussing the safety issue.

It was not a substitute for safety assessment but a "guiding principle which is a useful tool for regulatory scientists engaged in safety assessments".