Are there still travelling fairs? In many villages, they used to be part of the annual round. For weeks, the children’s anticipation would mount. Then the great day would come. Clowns, dodgems, candy floss: in those day no one knew about sugar-rushes so the brats grew delirious with excitement while the parents enjoyed themselves more than they let on. Does all that still happen – or do you have to go to Boris Johnson’s office for a similar spectacle?

On a smaller scale, I entertain my friends about once a year with a fantasy which does not require so many props. It is called the Anderson diet fair. I announce my determination to lose weight and my audience responds with unalloyed scepticism. In City parlance, when they hear the words ‘Anderson diet’, they are selling. This time, they may be wrong. As my eighth decade is not far over the horizon, doctors almost seem disappointed that I have not done myself more harm, but they have persuaded me that this will not last and that it is time to take health marginally more seriously.

So I am following three rules. Atkins and anti-carbohydrates: occasional lapses, but I have mostly been obedient. Giving up spirits: the odd back-sliding, but remarkable firmness of purpose. As for wine, up to three days of abstinence per week: so far, so compliant. Beyond that, try to cut down the quantity, and if the table wine is nothing special, leave it on the table. It helps that I have a female doctor whose shock when she worked out that I consumed 100 units a week was genuine. (I suppose that it does seem a lot to a girl, although I can think of some girls…) When I told a previous doctor how much I drank, he fixed me with a beady eye, saying: ‘Are you telling me the truth?’ ‘Well, more or less. I rarely drink more than a bottle and a half a day.’ ‘Because whatever figure a patient gives me, I normally double it. If I should be doing that in your case, I’m worried.’ I told him about a French anti-alcoholism poster I once saw: ‘Jamais plus qu’un litron par jour.’ Given that doctors exaggerate and that the frogs are a stunted race, this surely means that we could have at least two. He was unpersuaded.

The evening before I started my sentence, I dined with an old friend who is both wealthy and cautious. When he heard that I was about to go on a regime, he said that he was glad to have caught me in time, for he wanted my advice. When I heard the reason, I reassured him that whatever the restraints, I would have found the flexibility. There is dieting and there is lunacy. He had a problem. Shortly before the 2008 banking crisis, feeling passing rich and impressed by both tasting and reading about the 2005 clarets, he had plunged into that Bordeaux vintage. He did not regret this decision but it had unbalanced his cellar, especially as the wines were still locked up. So should he sell some? There were six of us. He provided seven bottles: Latour, Haut-Brion, Lafite, Margaux, La Mission Haut-Brion, Léoville-Las Cases, and Léoville-Barton, all opened at breakfast, all still barely ready.

We drank, we voted. I thought that the Haut-Brion came top, narrowly shading the Latour, with Lafite close behind. I felt that the Margaux was disappointing. The others were all excellent, as befitted their pedigrees. But none of us agreed. Someone actually put the Margaux first.

However, there was consensus around two points. How much should he sell? Nothing. How could he ensure that this was the correct decision? We would meet in committee every so often and re-taste the wines, adjusting our opinion if necessary. I am not sure whether his amusement betokened agreement. But the need to be around to discharge this essential responsibility is a further argument for dieting.