One of the features of the post-Brexit world - good or bad according to taste - will be that we will need to start making a range of decisions in London about environmental issues which have been, during the past few decades, increasingly made in Brussels.
This raises interesting questions.
The first question is whether we are going to operate on the same basic principles that have governed EU environmental policy - above all the precautionary principle.
My own hunch is that we will find a way of incorporating the precautionary principle into our policy-making after Brexit, and I welcome this because I think it is sensible to operate on a "no regrets" basis when it comes to the ecosystem. For example, where there is significant doubt about whether a particular chemical will have serious and unintended consequences, it makes sense to err on the side of avoiding risks.
But, if we are going to operate sensibly once we have to make our own decisions about these things, we will need to be careful to apply the precautionary principle in a balanced and proportionate way. This means sailing between the Scylla of machismo disdain for the possibility of untoward ecological consequences and the Charybdis of hysterical fear of science and its products.
An interesting example of the difficult balancing acts we will need to perform in future is provided by two families of chemicals about which the EU is currently making decisions, and about both of which we will need to make decisions in England in the years after 2019. I am sure this is going to be an area of huge controversy because there are groups lining up to ban both of these families of chemicals (glysophates and neonicotinoids) completely and groups equally determined that their use should be permitted without constraint.
Having looked into the various claims and counter-claims I have become persuaded that the way to the argument actually falls very differently in the two cases. So far as I can see, glysophates, if applied in the correct way and at an appropriate stage in the agricultural cycle pose no significant risks and should consequently be allowed subject to careful rules about how they are used; whereas although the evidence is not conclusive, there do seem to be strong enough reasons to worry about the effects of neonicotinoids on bees that make it sensible for us to ban their use until and unless it can be robustly demonstrated that the bee population will not suffer in the way that some of the science currently suggests it may.
As so often in public administration, the likelihood is that balanced and proportionate decisions will end up by being unpopular with all of the interested parties. It is well known that you cannot please all of the people all of the time. But it is possible to displease all of the people some of the time.