Researchers investigating organic farming have called for a genetically modified crop trial in Warwickshire to be abandoned after it emerged that it threatens the Henry Doubleday Research Association, Europe's largest organic institute.
They are concerned that if wind-blown GM pollen cross-pollinates organic crops at the HDRA, the centre could lose its organic status.
Government officials and Aventis Crop Sciences, the company that is carrying out trials of the GM maize crop, do not believe there is any chance of contamination across the 3km that separate the sites.
But Margi Lennartsen, head of international research and development at the HDRA, said she was deeply concerned.
Specialist investigations at the HDRA are carried out by 25 researchers on small plots at Ryton.
Dr Lennartsen said if the Soil Association withdrew organic status, it could halt work that includes projects on improving organic vegetable production and long-term assessment of non-commercial crop treatments.
"We can only carry out organic trials if we have accredited organic land, and these GM trials obviously threaten that," Dr Lennartsen said.
Bill Bourne, head of biological sciences at Coventry University and vice-chairman of the HDRA council, said: "The GM trials should be stopped, not only because of the potential damage to a nationally important research site but also because we are not convinced that the products that are being tested are of any particular value."
Collaboration between Coventry and the HDRA involves four joint projects, two joint PhDs and three students on placement.
Nic Lampkin, coordinator of the organic research unit at Aberystwyth, felt that the proximity of a GM trial to Ryton was a problem.
"The ability of this strategically important centre to carry out experimental trials would clearly be affected by any loss of status," Dr Lampkin said.