When he was in the government, headlines referred to Michael Howard by his surname. This tradition has been resurrected in the past couple of weeks. Headlines don't read: "Mike says he will lower taxes".
Unlike Labour leaders, Tories are rarely known by their first names. It's Tony and Cherie or Gordon and Sarah, but never Iain and Betsy or William and Ffion. Perhaps Smith was deemed too common, but Iain Duncan Smith was never Iain either - only IDS, recalling IBS, the abbreviation for irritable bowel syndrome.
For politicians, names are part of their public image. See ''Tony'' in a headline and we know it's about the PM. With casual shirts and mugs emblazoned with pictures of his children, it gives a sense that he is just an ordinary man doing an extraordinary job. For Ken Livingstone - known as Red Ken, Ken, or Ken Livingstone, but rarely just Livingstone - his name is part of his man-of-the-people image. Had he been called Piers or Sebastian, he might have trouble maintaining that image.
Surnames are usually used for dictators. We do not refer to Benito, Joseph or Augusto but to Mussolini, Stalin or Pinochet, though we might refer to, say, Uncle Joe when a tyrant is temporarily on our side. We use nicknames when we wish to be mocking or irreverent: Dubbya for George W Bush or Maggie for Margaret Thatcher. The latter was rarely Margaret.
Writers, too, need to think about their names. When I was first published, I used my proper name, Eleanor. Eleanor has political clout - think Eleanor Roosevelt or Eleanor Marx, even Queen Eleanor of Aquitaine. I can think of no Queen Ellie or of any politician called Ellie. But then I decided that, though it may sound less grown-up, it was easier, when drunk, to introduce myself as plain Ellie (as I was always known by family) than to trip up over the Ls and Ns in Eleanor Levenson.