Pressure groups that have raised concerns about GM food have reacted angrily to claims that they skew scientific research to suit their own agendas.
The allegation is just one of a number of stinging criticisms levelled at the Soil Association, Greenpeace and Friends of the Earth by Sir John Krebs, the outgoing chairman of the Food Standards Agency.
In his parting shot in The Times last week, Krebs said: "Some of these groups that have single issues to pursue tend to be selective in using the scientific evidence."
But Peter Melchett, policy director at the Soil Association, was scathing. He said: "Krebs has been consistently biased and was pro-GM foods long before his appointment as the chairman of the FSA."
Ben Ayliffe, a GM campaigner at Greenpeace, agreed: "Krebs claims he's impartial, but that's rubbish. He has always had his knickers in a twist on the issue."
Krebs once claimed that people who pay over the odds for organic produce are wasting their money. However, an official review by former trade union leader Baroness Dean, commissioned by the FSA and placed on the organisation's website without any announcement, is critical of the stance it has taken on GM and organic foods.
Tony Juniper, director of Friends of the Earth, said: "We base our work on sound scientific evidence. Our policies are not aimed at gaining a higher membership but at making significant changes in the real world for the benefit of everyone, not just a select few."