Only one very new to the trade would be so gauche as to take out a notebook, or use the back of an invitation, to scribble out a diary paragraph on the spot. The more experienced practitioner stores the details in the head and, after a decent interval, ambles to the Ladies' or Gents' to jot them down in comfort.
Gossip columnists have no friends, only contacts. They are the most manipulated of journalists. Many of their stories - more in some columns than others - are written at the behest of their subjects. Anyone not wanting a mention would be well advised to shun them.
A good gossip columnist is a rare beast, prized by its owner and commanding a high fee on the newspaper transfer market - which explains why the best ones stay put longer than colleagues in less-exposed posts. Their craft requires a unique blend of high professionalism and extreme self-delusion.
You need a journalist's most advanced technical skills, for a good diary paragraph is a model of compression. But you must also be able to convince yourself that the world you are writing about - packed with styrofoam characters leading empty lives at the tops of their voices - is of importance and interest. It is a world where truth is not stranger than fiction, but indistinguishable from it.
Important this little world may not be, but if the columnists are doing their jobs it will be of interest, in the same way that Coronation Street is. The cast of characters is small and they recur. Once we have been persuaded to interest ourselves in them, we look forward to reading what they do next.
Why has Camilla Smartyboots, the 24-year-old daughter of Wykehamist (rule one: no gentleman must be mentioned without his school) bank executive Jonathan Smartyboots, 53, been spotted in Gstaad with the Hon Tim Squeezy, 28, the Old Etonian toothpaste heir? Didn't we read last week that Camilla was the constant companion of Belgian racehorse owner Jacques Burque, 44 (rule two: schools don't matter for Belgians)? Indeed didn't we see a snatched picture of them, arms entwined, outside the Peppermint Lounge? Life moves on and all, in the characteristic staccato style, will be explained.
Gossip columnists do not travel a lot - they would miss too many parties - and when they do it is to predictable places. The only people left in Britain who believe real society folk spend most of their time at the races, they put on morning coats every year for the four days of Royal Ascot and the Derby.
Cheltenham in March is another safe bet and, for the really adventurous, the Prix de l'Arc de Triomphe at Longchamps in the autumn. They go to Wimbledon for the tennis, the strawberries and the nudge- nudge about the sex lives of the burly women players. They go to the Cowes regatta for no reason except that they have always gone there. Occasionally they will be allowed the odd week in New York, not because anything interesting is going on but because it makes them feel good.
The demise of gossip columnists has long been predicted. Their work is based, after all, on notions of class and privilege that we like to believe are outdated. While the columns survive, we shall know we are wrong.