Quite properly the Chief Medical Officer declined to do the Maths in public for his worst-case scenario. He intends and expects that the UK will do much better. It’s not difficult to plug in the figures however. A population above 60 million, a “high-end” estimated infection rate of 80%, and mortality at 1% suggests that, to extrapolate the Prime Minister’s phrase, families here could lose half a million loved ones over the next four or five months during which Covid-19 is expected to peak and decline.

Such a calamitous outcome would double the “normal” annual death rate here and more than match the toll of 1918/1919 Spanish flu. Mercifully, as Sir Chris Witty made abundantly clear, it need not happen here so badly this time if we all take three simple precautions: wash hands frequently, stay home immediately at the first inklings of a cough and temperature, and ensure that the vulnerable, mostly elderly, are better looked after.

Normally a diary column like this is a miscellany of musings and observations, but it’s impossible not to be overwhelmed this week by the pandemic in our midst. Many years ago the veteran reporter John Sergeant explained to me his theory of “the engine of news”. There is always some continuing story which editors can fall back as the backbone of a bulletin on a slow day. The Middle East has played this role a number of times since the 1967 Israel-Arab War. So in some years have American or British politics. Margaret Thatcher was a great running story which another mentor, Jon Snow, wisely advised me not to bail out on to take up a foreign posting in the mid-1980s.

From 2016 until now there are no prizes for guessing that Brexit was the news engine. But that’s “done” now. Those phlegm-flecked wasted years of division were fading from our memories even before this abominable bug broke out of China.

I suspect that Coronavirus is more important than Brexit and certainly not just something to fill the airwaves and columns of print for months or a few years on end. It is bigger than that.

In recent times there have been events every decade or so of such magnitude that they have unforeseen consequences, ultimately changing the lives of everyone around the world, and the assumptions we make about it.

In 1989 there was the fall of the Berlin Wall. The collapse of Soviet Communism ushered in the “unipolar moment” for the US and its “New World Order”. In 1991 Tim Berners-Lee launched the World Wide Web. The attacks of 9/11 2001 brutally proved that there had been “no end of history” instead throwing the Middle East and Maghreb into turmoil which has yet to end and displaced many millions of people. The banking crisis of 2007/8 is widely credited with leaving so many behind that populist strongman-style leaders seized their moment.

Now, in 2020 Coronavirus. It’s frightening. We are all having to change the way we live to combat it. Just a few of the questions raised by the outbreak are about globalisation, industrial supply chains, animal rights and what we eat, freedom of movement of people, national spending priorities on health and welfare, triaging to help those most likely to benefit and how, where and with whom we work and share our lives.

For politicians it means a sea change in the public mood. If things go wrong and they are blamed, the world’s two most powerful men Presidents Xi and Trump, could lose their grip on power.

Boris Johnson could find himself dispensed with after a decent interval too. So far the public mood is with him. After the post-referendum excesses the British character seems to have reverted to what it is traditionally known for around the world, a mixture of common sense, keep calm and carry on, and determination to see things through. I notice hardly any face masks as Londoners go about their business and leisure, but nobody is shaking hands. The Blitz spirit is appropriate to the virus in way it never was during the Union Jack underpants phony war with Brussels.

Once this outbreak is over things will never be the same again, though it is impossible to say what those transformative shifts will be.

There is almost nothing good to say about Coronavirus breaking out from hotspots to become a global pandemic but I think I’ve found something. The spread means that we no longer have to listen to over-excited reporters mispronouncing Lombardy. For some reason, perhaps to sound more foreign and in the know, there was an outbreak of calling it LomBAAHdy – a pathetic halfway house to the Italian Lombardia. Like Normandy and Burgundy, Lombardy has been a proper English word since at least the Renaissance. The Bard (geddit?) refers to the region several times in his plays, “fruitful Lombardy, the pleasant garden of Great Italy”. What’s good enough for Shakespeare should be good enough for the BBC Pronunciation Unit. Lombardy will survive Covid-19.