In his recently submitted written submission to the House of Commons Environmental Audit Committee enquiry into Insects and Insecticides, Professor Dave Goulson, of the University of Stirling, one of the authors of the much quoted recent research paper on the impacts of neonicotinoid insecticides on bumblebees says:
I am concerned that Defra’s response to this work, and other studies, seems to be focused on trying to pick small holes and then using them as a justification for inaction. No study is perfect, and in practice it is impossible to carry out the ideal study. I would be happy to explain this in detail, but in essence a proper experiment requires natural, free flying bees in multiple areas with and without neonicotinoids. There are not areas without neonicotinoids in Europe. Hence if Defra are waiting for the perfect experiment to be performed, they will be waiting a very long time.
The full text of the submissions is here. They make grim reading.