The results of a three-year field trial of genetically modified, herbicide-tolerant useful plants in Great Britain were published in mid October 2003, reports the German Manufacturing and Trade Association for Natural Food and Products (BNN). One of the findings of the study is that the cultivation of herbicide-tolerant spring-sown oilseed rape and sugar beet represents a distinctly greater risk for birds and insects than previously assumed. Overall, the use of these plants and the associated broadband herbicides causes a definite reduction of the variety of herbs in the fields, which means that many forage plants for insects, butterflies and birds are no longer available. Four studies on the cross-pollination potential of oilseed rape, maize and sugar beet come to the conclusion that the cross-pollination distances have been previously underestimated. For example, break crops of oilseed rape were still pollinated with transgenic pollen even at a distance of 26 km. Moreover, oilseed rape from the seedbank still emerges on fields for many years, which can lead to high contamination of the crop.