Fergus Walsh reports: " The rat experiments were dismissed as flawed"

Dr Pusztai claimed rats in his Scottish laboratory suffered damage to their vital organs and immune systems as a result of being fed GM potatoes.

But the panel of six toxicologists, appointed by the influential Royal Society, has dismissed the research as irrelevant and inconclusive. It said the work undertaken by the Hungarian-born scientist was flawed in many "aspects of design, execution and analysis".

The panel said: "It would be unjustifiable to draw from it general conclusions about whether genetically-modified foods are harmful to human beings or not."

Scientific protocol

The Royal Society's Professor Patrick Bateson explains what was wrong with the research

Dr Pusztai lost his job at the Rowett Research Institute in Aberdeen as result of his claims, which he made on television last summer.

The institute said he had ignored scientific protocol by going public with his claims before the research had been peer reviewed and published in a recognised scientific journal.

The potatoes contained a gene from the snowdrop

Nonetheless, the claims were the catalyst for the big debate on GM crops and food now underway in the UK. The row came to a head in February when a group of 20 scientists held a press conference to declare their support for Dr Pusztai.

Summoned before the House of Commons Science and Technology select committee, Dr Pusztai stood by his claims and said he had no regrets. The committee, which also published a report on Tuesday on the handling of the whole affair, said the UK risked losing the benefits of GM technology unless the government led a rational debate on the issue.

Snowdrop gene

BBC's Gerry Northam: The row over GM food is changing the relationship between government and scientists

Dr Pusztai's £1.6m research project, was funded by the Scottish Office. He modified potatoes to contain a gene from the snowdrop. This produced a natural insecticide, lectin, in the potatoes.

When these were fed to the rats over a period of 10 days, Dr Pusztai claimed some of their organs shrank or did not develop properly, including the kidney, the spleen and the brain. He said the rats' immune systems also suffered.

The Rowett removed Dr Pusztai from his post

However, the Royal Society Working Group said: "We found no convincing evidence of adverse affects from GM potatoes.

"Where the data seemed to show slight differences between rats fed predominantly on GM and on non-GM potatoes, the difference were uninterpretable because of the technical limitations of the experiment and the incorrect use of statistical tests."

The panel said the whole episode underlined the importance of scientists exposing their work to critical appraisal from their colleagues before releasing information to the public.

Further research

Jack Cunningham has welcomed the panel's findings

The working group stressed its report related solely to Dr Pusztai's research and said other studies on the health effects of GM food would be needed to resolve the arguments over the safety of the technology.

"There are going to be new foods which must be analysed properly and they must be done to the highest scientific standards and peer reviewed, and then published in the public domain," Professor Patrick Bateson, vice president of the society, said.

The working group said there was incorrect use of statistical tests

Dr Jack Cunningham, who has taken responsibility for GM foods in the Cabinet, welcomed the findings of the Royal Society Working Group. A report by the UK Government's Chief Medical Officer to be published in the next few days would echo the findings of the panel, he said.

The pressure group Friends of the Earth, which has campaigned against GM foods, said the report from the Royal Society did not change its view of the dangers - both to human health and to the environment - of GM foods.

Oxford University's Professor Chris Leaver debates GM food with Tony Juniper

"There's no concrete proof that they are safe," said its spokesman Tony Juniper.

"The public are concerned about the use of biotechnology in agriculture and I think they are behind the British Medical Association (BMA) which is calling for a pause so that we can properly assess the upsides and downsides of the application of biotechnology in food."