A propos of nothing, years ago when we lived in Belgium, on a walk we came across a patch of the biggest blackberries we had ever seen - they were almost the size of golf balls. But covered in dust from a nearby cement works, so completely useless. Even after washing you couldn’t have risked eating them. The irony was, so we were told by a local resident, that during the war, the occupying Germans fitted filters in the factory to stop it belching all this stuff all over the local countryside and after the war, the Belgians removed them because the Germans had fitted them and never replaced them with anything else.