Labour could
wait for that relationship to go wrong. But there is no guarantee that voters will then return to Labour. The Brexit party, or some other, yet-to-be-formed vehicle for nationalism, or regional pride, or nostalgia, may appeal to an ageing electorate more.
Labour will probably have to accept that some of its old “heartlands” are gone for good. In the cities, and in growing southern towns such as Swindon, which New Labour won and the party has since lost, Labour will have to build new ones.