But in any case, the chances of the GM pollen establishing a foothold in British plants seem vanishingly small. It may land on the stigmas of native plants like wild mustard or wild radish, and it may pollinate them. But the chance is very low, and the chance of a viable hybrid developing is lower still. If one or two per cent of the rapeseed crop contains GM material, then you're talking of something orders of magnitude less than that when it comes to the chance of the modified gene getting into another species. And even if it does it won't matter, because the herbicide-tolerant gene confers no advantage on that species, so it will die out very quickly.
Rape seeds are like small greasy ball bearings, and they escape quite easily.
So they could perpetuate the gene flow. The answer is to spray the volunteers with another herbicide next spring, and then there should be no problem. Insects harmed But other concerns will persist. Organic farmers whose land abuts GM crops, or bee-keepers whose hives are within flying distance of them, probably cannot avoid GM material getting into their produce. And there may be effects on non-plant species as well.