The cost of attacks against genetically modified-crop trials emerged this week as more British plant scientists left the country to pursue their work abroad unmolested.
Institutes say attacks damage staff morale. Many researchers feel there is no future for them in the UK. The plant science department at the University of Cambridge is losing three scientists, two of them to Australia.
Mark Tester, head of plant science at the university, is moving to the Waite Institute, Adelaide, in search of a safer environment and better funding. He said: "Industry has left in droves and that reduces the options for researchers and students."
Twenty-eight incidents of vandalism targeted at basic plant research trials were reported between January 1999 and April 2003, according to preliminary findings conducted by the independent trust Sense About Science. These are in addition to 52 incidents reported against the government's field-scale evaluations programme, which tests the safety of GM crops.
Protesters trampled, cut and pulled up crops, according to reports gathered from the six basic research institutes and four contracting institutes that account for the bulk of UK field research.
Basic research trials have proved particularly vulnerable. Tracey Brown, director of Sense About Science, said: "You can destroy a small-scale trial with a pair of garden shears."
In 90 per cent of such cases, research was written off, including an investigation into crop drought resistance suited to sub-Saharan Africa.
Although the report found the number of attacks was declining - two instances so far this year - almost half said they had received threats.
Chris Leaver, head of plant sciences at the University of Oxford, has been the victim of personal threats as a result of taking part in the GM debate.
He has recently gone ex-directory to stop abusive telephone calls and faxes.
Michael Wilson, chief executive of Horticulture Research International, said the vilification of research in this area was grinding scientists down. He has received considerable abuse over the past five years, and had to call the bomb squad to his home on one occasion. "It is uncomfortable and probably a little cavalier to be as outspoken as I am. And what's the point? You do wonder if you are raising your blood pressure for no good at all," he said.
The survey found institute directors were becoming ambivalent about debating the issues in the media as they felt past attempts had made them targets.