Matthew d’Ancona asserts that “the vigorous exchange of goods and labour is the greatest engine of prosperity the world has ever known” (Brexit meets Trumpism: the new special relationship, 14 November). Had he prefaced his remark with “the fair and vigorous exchange” I might have agreed with him. As it is, his comment is a meaningless mantra. Prosperity for whom? For a few, certainly, but not for millions of people in former manufacturing and mining…