The prime minister’s Mandelson blind spot points to a wider truth about him: his steady, calm persona was never quite the full picture. Brutal sackings, drift, and a failure to read people, risks and consequences suggest a leader very different from the one voters thought they had chosen, writes Anne McElvoy I t was exactly a year ago this weekend when Lord Mandelson stepped out to host his first weekend of celebrations as the new British ambassador to America. In full fig, he appeared in