"Otherwise all new "zero tolerance" policies would be unlawful" - surely it's the other way round?

If there is an absolute requirement to enforce the law anything other than a zero tolerance policy would in fact be illegal, and every council and police authority in the wounctry would be in serious trouble, because nobody could possibly enforce all the laws completely.

I seem to remember people speculating whether various bizarre laws (against mince pies and so forth) could in principal still be used, if they had never been repealed. The official line seemed to be that, by being allowed to fall into disuse for so long, they had in fact become uninforceable.

"A case of estopel" - isn't that one of those East European wines?