In 2002 DEFRA funded a five year research project on rat control strategies costing £400,000. This included some work on use of a new rodenticide. The final report is available on the DEFRA website at:
A Government funded survey was carried out in the 1990s which looked at resistance to anti-coagulant rodenticides and concluded that rodenticide resistance was becoming a significant problem in many areas.
On behalf of UK Government, the Health and Safety Executive delivers the regulatory authority role in relation to the use of rodenticide products in the UK. Last year, following agreement by the chairman of the Advisory Committee on pesticides, the HSE gave emergency approval for outdoor use of brodifacoum at one site in Winchester on the basis of an assessment that rats there appeared to be resistant to other treatments. Risks to wildlife (the reason outdoor use is not normally permitted) could be managed since it is a relatively enclosed site.