UK farmers who value their Single Farm Payments – and there are many whose accounts would not look well without them – may not be keen to see any change in the UK’s membership, but there could be an increasing number who think differently.  Not because of any enthusiasm for the politicians who argue for the UK to leave, but because of the threat to their businesses posed by the EU approach to plant protection.

Three EU policies pose commercial threats –­ the complexity of the process for obtaining approval of a product for use within the EU, the Water Framework Directive as implemented by national governments and the recent restrictions on neonicotinoid seed treatments.

Member states used to be responsible for approving pesticides for use in their own countries. That changed in 1993 when an EU Directive came into force, requiring any active substance (including those then approved) to meet specific safety and efficacy criteria before it could sold within the EU. The number of approved substances shrank dramatically and only those whose potential market justified the expense remained approved, and even those just for a limited period.

In 2011 a new EU Regulation came into force which fundamentally altered the basis for approval, by changing the assessment from risk based to hazard based. The eye of the approval needle has become even smaller. Any exposure to a ‘hazardous’ substance is now unacceptable. If coffee was submitted for approval, it would be banned because caffeine is harmful if taken in sufficient quantity; that it has been used for centuries with small exposure and little or no risk would be irrelevant. So products previously approved may no longer be.

The Water Framework Directive and its "daughters", the Drinking Water Directive and the Groundwater Directive, require rivers, lakes, ground and coastal water to reach good ecological and chemical status, limit the amount of pesticides and chemicals in drinking water and protect groundwater. The standard is 0.1 microgramme per litre, the equivalent of one paracetamol tablet in an Olympic sized swimming pool. Additionally the WFD requires that the quality of water for drinking should not be allowed to deteriorate and require additional treatment.

The combined effect of these Directives and the actions of member states to implement them may lead to severe reductions in available pesticides, especially in the UK where more land than in many other member states is under-drained, thus leading to pesticides moving quickly into drains and then watercourses before breaking down in the soil.

In December 2013 the EU prohibited the use of three neonicotinoids as a seed dressing for flowering and spring planted crops. These systemic insecticides were used to treat 70% of the UK crop of oil seed rape in 2012. Studies have suggested that they have led to a decline in the bee population, but others have found no effect when used in normal field situations, leading to claims that the EU Commission has not reviewed all available data.