A man not permitted to play tennis with his wife on a public court, though they sleep together, is just one of the absurdities of the latest coronavirus restrictions. But you can see the point. If two people can play tennis, why can’t others? How can we know they are in a bubble or not? A similar restriction applies to golf, where people play against others. Unless of course it’s an objection to golf being a toff’s game: a sort of mean-spirited attitude emphasising the fact that we’re all in this together.

None of this applies to open air swimming. You swim alone. There is no need for a second person, and those who do it are from a mixture of social classes. The only thing they have in common is a liking for the buzz they get after swimming in cold water. And, of course, the health benefits to the immune system. One swimmer I know caught a very nasty case of Covid-19 and was hospitalised. In the hospital he was one of ten people admitted to intensive care for Covid-19. Six died, three survived in reduced health and only he, the cold-water swimmer, fully recovered.

It’s a lifeline to health, both physical and mental

Another swimmer was knocked down by a London bus many years ago. Standing on a pavement in Oxford Street he was hit by its wing mirror. Cardiac arrest. Intensive care, and he returned to outdoor swimming. Fully recovered. Many of us swim all year round. We are, as they say, acclimatised and don’t worry when the temperature dips to 12 degrees, at which point the boundary rope is partly drawn in. We continue as the temperature slowly drops to 4 degrees when water reaches its greatest density. At that stage there is no difference between the surface and the depths, which reach 20 feet at the lowest point. And we continue as ice forms on the surface.

When the first lockdown came in March this year, the temperature was on the way up, so we all knew the pond would get increasingly busy and crowded. It was closed. Until it reopened in September. Now it’s closed again. Yet with an area of some 3,000 square yards and usually less than 10 people in the water at any one moment, during this time of year, that is 300 square yards per person. The changing area is more crowded, but with colder air temperatures people do not hang around. There are no warm showers at the men’s pond, and the changing area is open to the elements apart from a short roof around the perimeter to keep clothes dry from any rain.

As the water temperature declines there will be fewer people, and the facilities will be used less rather than more. So why close it? The Corporation of the City of London is in charge and should appeal against the government’s diktat. And the government should listen, because it’s a lifeline to health, both physical and mental.

Government policy is said to be based on the numbers, but there has been no known infection at the pond, and swimmers need to remain acclimatised as the temperature dips. As Theresa May has said, “It looks as though the figures are being chosen to support the policy, rather than the policy based on the figures”.

So those of us who wish to swim in ever colder water should be allowed to take this miraculous prophylactic that helps us avoid dementia — not a small consideration at my age — keeps the immune system in shape, and harms nobody. No one is compelled to do it, but those who wish to continue as the weather cools should be commended for their fortitude.