BBC Science Correspondent Pallab Ghosh: "Credibility is an issue"

The panel of experts who were asked to peer-review the work are understood to have told the journal that the research is "unsound" and should not be published.

One of the referees, Professor John Pickett, from the Institute of Arable Crops Research in Hertfordshire, told the BBC that publication of the research, expected this Friday, would do immense harm to the image of the journal.

"Since I understand that a number of us were very, very critical of the work and yet the journal is going to go ahead and publish this information with its conclusions, then we have decided to speak out."

"If this work had been part of a student's study, then the student would have failed whatever examination he was contributing the work for.

Primetime TV

Dr Pusztai claimed last year that GM potatoes fed to rats damaged the animals' stomachs, immune systems and stunted their growth. His concerns, which were aired on primetime TV, sparked a major debate in the UK on the safety of GM foods and led to calls for a moratorium on the development of GM crops.

The Hungarian-born scientist's outspoken comments ultimately cost him his job at the Rowett Institute in Aberdeen, and the Royal Society later rejected his work as "flawed in many aspects of design, execution and analysis".

The potatoes contained a gene from the snowdrop

The Lancet paper is believed to be an examination of the rats' stomach linings by Dr Stanley Ewen, a pathologist at Aberdeen University.

He is thought to claim these were thickened and inflamed in the rats which ate the GM potatoes but not in the control rats.

The GM potatoes had been engineered to produce a lectin insecticide. The control rats were fed potatoes simply spiked with the lectin. The suggestion is that the GM process itself was responsible for the changes seen in the rodents.

The journal says alongside the work: "In publication of these papers, The Lancet aims to make constructive progress in the debate between scientists, the media, and the general public about the safety of GM foods."

'Serious view'

"It is quite amazing that they are going to publish work which is so inadequate," said Professor Pickett. "It isn't customary to publish papers and offer a critique of them. Either you publish them because they are OK or you don't publish them."

The Royal Society will counter any comments or claims that are made in The Lancet.

Dr Pusztai wants "transparency" on GM research

"If they publish without any disclaimer or without making clear the reservations of the reviewers, then we would take a very serious view of it," says Steven Cox, the Royal Society's executive secretary.

Dr Pusztai has set up a Website to make known his feelings about his research and the way he believes he has been treated by the scientific establishment. On it, he writes: "I think the whole thing stinks."

He says the Royal Society's criticisms in May were unfair and hopes to convince scientific colleagues that its criticisms were based on incomplete knowledge.