One would have thought this particular can of worms might, after nearly 80 years, be well past its sell-by date. But books about Mrs Simpson and her infatuated king appear with thudding frequency, each with some ever more far-fetched theory about this curious union. Now comes the leaden hand and leaden prose of Andrew Morton, with yet another: that Wallis was, all her life, in love with another man long before, during and after her experience of vitriolic abuse, first as the besotted prince’s obsession, then scapegoat for his abdication, and object of vilification during her years as his wife.

This...