And then I had a ghastly vision. What if this is it? What if this is the long-awaited inflexion point – the moment that has been prophesied since the Eighties? What if winter is over – for ever?

Aaargh, I thought: and in that moment of horror, I contemplated the loss of something so intrinsic to our psychology. Imagine: no more snow. No more tobogganing on Primrose Hill, no more waking up to see the magic prints of the dog on the lawn.

Imagine if this unseasonably warm spell is just the beginning of a long period of meteorological mediocrity: no more ice on the canal, no lovely crispness in the air, no excuse to walk into a room with a fire and go “brrr” while theatrically rubbing your hands.

Imagine if we have nothing in these long, dark months save a muggy and melancholy mildness, soft, damp and unwholesome; nothing but rain and a louring grey sky pressing down on our hungover eyeballs. The thought made me feel almost unwell.

In my despair, I rang the great physicist and meteorologist Piers Corbyn. You know Piers: he is the older brother of Jezza, and he is famous for believing that the world – on the whole – is getting colder, and that the whole global warming theory is unsound, to say the least. Piers thinks that whatever the role of humanity in affecting the temperature of the planet, that role is pitifully trivial next to the Sun, the supercolossal boiling ball of gas about which we revolve and which enables life on Earth.

In the view of Piers and his colleagues at WeatherAction, it is all about sun spots, and he is on record as believing that we are now due for a new “Maunder Minimum” – like the famous cold spell in the 17th century, when the Thames froze several times.

“Piers,” I said – and I felt like the children of Israel, denouncing Jeremiah for getting it wrong – “what about the new Ice Age? Where is it?”

And Piers did his best to calm me down. “Helmsman!” he said (since that is how he addresses me). “Relax. Winter has not gone.” And he went on to argue, quite persuasively, that there are plenty of places that are really very cold at the moment – the west of the USA, for instance. He reminded me of the prodigious snows that hit the eastern seaboard of America last winter. Yes, it is warm in the UK at the moment – amazingly warm – but the UK and its territorial waters amount to only one six-hundredth of the planet.

The current mild spell would last till the end of January, he said, and it would then turn bitterly cold in February. Whatever is happening to the weather at the moment, he said, it is nothing to do with the conventional doctrine of climate change.

And there, of course, he is in agreement with the vast majority of mainstream science. Meteorologists of all kinds – climate change sceptics and believers – can see the difference between climate and weather; between randomly occurring changes and deep, long-term trends.

We ordinary human beings are not so rational; we are no different from all earlier cultures in that we have to put ourselves in the story, and to attribute this or that individual weather event to our own behaviour or moral failures. Think of Agamemnon at Aulis, unable to get the wind he needed to sail for Troy. What was the problem? He had shot a deer sacred to Artemis. And the solution? Sacrifice his daughter! It was all about him, him, him.

Scientists look at the data. But everyone else just looks at the weather – and it is the weather, therefore, that makes the psychological difference to the debate. Look at the recent summit in Paris, which ended in a good agreement to cut CO2, in contrast to the debacle at Copenhagen six years ago. What was the real difference? It was the weather. Paris was ridiculously warm for December. Six years ago, Copenhagen saw the biggest snowfalls anyone could remember. “Global warming?” everyone asked.

It is fantastic news that the world has agreed to cut pollution and help people save money, but I am sure that those global leaders were driven by a primitive fear that the present ambient warm weather is somehow caused by humanity; and that fear – as far as I understand the science – is equally without foundation.

There may be all kinds of reasons why I was sweating at ping-pong – but they don’t include global warming.

That brings us to Vladimir Putin. I was in Paris at the end of last week, and the Russian leader’s face glowered sulkily from every billboard. “Poutin”, said the headline, “Notre nouvel ami”. Many French people think the time has come to do a deal with their new friends the Russians – and I think that they are broadly right.

Look, I am no particular fan of Vlad. Quite the opposite. Russian-backed forces are illegally occupying parts of Ukraine. Putin’s proxy army was almost certainly guilty of killing the passengers on the Malaysia Airlines jet that came down in eastern Ukraine. He has questions to answer about the death of Alexander Litvinenko, pitilessly poisoned in a London restaurant. As for his reign in Moscow, he is allegedly the linchpin of a vast post-Soviet gangster kleptocracy, and is personally said to be the richest man on the planet. Journalists who oppose him get shot. His rivals find themselves locked up. Despite looking a bit like Dobby the House Elf, he is a ruthless and manipulative tyrant.

Does that mean it is morally impossible to work with him? I am not so sure. We need to focus on what we are trying to achieve. Our aims – at least, our stated aims – are to degrade and ultimately to destroy Isil as a force in Syria and Iraq. That is what it is all about.

Our mission is to remove an evil death cult, to deprive their organisation of the charisma and renown that goes with controlling a territory of some 10 million people. We need to end their hideous administration of Raqqa, with its torchings and beheadings. We need them out of Palmyra, because if Syria is to have a future then we must protect its past.

We cannot do that without terrestrial forces. We need someone to provide the boots on the ground; and given that we are not going to be providing British ground forces – and the French and the Americans are just as reluctant – we cannot afford to be picky about our allies.

We have the estimated 70,000 of the Free Syrian Army (and many other groups and grouplets); but those numbers may be exaggerated, and they may include some jihadists who are not ideologically very different from al-Qaeda.

Who else is there? The answer is obvious. There is Assad, and his army; and the recent signs are that they are making some progress. Thanks at least partly to Russian air strikes, it looks as if the regime is taking back large parts of Homs. Al-Qaeda-affiliated militants are withdrawing from some districts of the city. Is that a bad thing? I don’t think so.

With Russian air support, the Assad regime is only a few miles from Palmyra – the fabled pink-stoned city of monuments, where Isil decapitated the 82-year-old curator, Khaled Al‑Assad, before beginning an orgy of cultural destruction.

Am I backing the Assad regime, and the Russians, in their joint enterprise to recapture that amazing site? You bet I am. That does not mean I trust Putin, and it does not mean that I want to keep Assad in power indefinitely. But we cannot suck and blow at once.

At the moment, we are in danger of treating our engagement as if it were some complicated three-sided chess game, in which we are trying to neutralise the Islamists while simultaneously preventing Putin from getting too big for his boots. If we try to be too clever, we will end up achieving nothing.

This is the time to set aside our Cold War mindset. It is just not true that whatever is good for Putin must automatically be bad for the West. We both have a clear and concrete objective – to remove the threat from Isil. Everything else is secondary.

Think of all those planes above Syria – some for the Assad regime, some against the regime, some against Isil, some against the non-Isil rebels. It is absurd. The best hope of getting rid of Isil is an agreement between all the powers – America, Russia, France, Britain, Turkey, Saudi Arabia and the rest – to take them out, together with a timetable for Assad to step down and a plan for a new Syrian government.

Everyone in Paris last week seemed familiar with one quotation from Sir Winston Churchill. When Hitler invaded the Soviet Union, Churchill decided to qualify his lifelong hatred of communism. “If Hitler invaded Hell,” said Churchill in 1941, “I would make at least a favourable reference to the Devil in the House of Commons.” And as he foresaw, it was the Russians who did the most to help us win the war.