The results of the Government's latest farm-scale evaluation GM crop trials provide valuable information on the management of these crops, according to the NFU.

The Scientific Steering Committee (SSC) presented the four-year field trials for winter oilseed rape to Defra this week.

The findings highlighted the impact on wildlife of growing and managing GM winter oilseed rape compared to its non-GM equivalent.

The findings revealed no significant differences overall between GM and non-GM crops in terms of insect life. Differences in crop type, herbicides and weed control practices and not the use of genetic modification was found to impact on biodiversity. NFU crop trials spokesman Bob Fiddaman said: "The results have identified few differences between GM and non-GM crops and must be viewed in the broad context of agricultural management systems.

"Herbicide use, weed control practices and differing crop types, not the use of genetic modification influences biodiversity.

"The NFU believes UK farmers should be able to access technologies available to their competitors. However, the market place will be the ultimate driver and British farmers will only begin commercial production of GM crops if it represents a clear business decision."

Environment Minister Elliot Morley said: "I am very pleased that all results of this study, the biggest of its kind conducted anywhere in the world, are now available.

"The trials demonstrate the Government's precautionary approach on GM crops and our firm commitment to case-by-case decisions underpinned by sound scientific evidence. I would like to express my gratitude to Professor Chris Pollock and members of the Scientific Steering Committee that oversaw the research programme and I look forward to receiving ACRE's advice on the final results which we will consider very carefully."

The results on winter oilseed rape will now be passed to the Government's statutory advisory body - the Advisory Committee on Releases to the Environment (ACRE).

The Secretary of State will ask ACRE to advise on the environmental implications for the commercial growing of the GM oilseed rape involved and the wider implications of the results for sustainable agriculture.

The results of the three spring-sown crops - beet, maize and spring oilseed rape - tested in the Farm Scale Evaluations were published in October 2003.

Winter oilseed rape is sown in autumn and is economically the most significant of the crops studied in the Farm Scale Evaluations.