I thank David Melding for that. He's absolutely right: the polluter-pays principle is centrally important here. Industries that cause industrial pollution must take responsibility themselves for reducing that pollution. They must pay for the cost of regulation as well.

The best available techniques come under the industrial emissions directive and are the practical ways in which that directive is given force, because it requires companies that emit industrial pollution to demonstrate that they are taking advantage of the most recent techniques available to reduce environmental impact from their industrial activities. 

As I said to David Rees, there is a job of work to be done in persuading the UK Government that that regime, which has served us well and can continue to do so even more effectively in the future, is not set aside when we leave the European Union, finally, at the end of this calendar year.