“We have to be humble in the face of nature.” Boris Johnson, whose response to difficult realities has always been to work very hard to disguise dismissive arrogance, was addressing the nation, again, about the virus, again.

Was his message “go to a restaurant”? No, that was three months ago. Was it “get back on the train and get into the office”? No, that was two months ago. Was it “we don’t need a national lockdown”? No, that was two weeks ago.

Two weeks ago, in fact, Johnson mocked the idea of a national lockdown, when it was proposed by the Labour leader, Sir Keir Starmer. Imagine, he told parliament then, telling businesses to close for two weeks. Starmer, he said, should “change his mind and think the better of his actions”.

Well. Minds have indeed changed. And, to be fair, it won’t be a two-week lockdown.

The event had begun late, of course. One advantage of all journalism being done remotely in these infectious times is that the public learns what every reporter knows, that nothing ever starts on time. The press conference was going to be at 4pm, and then 5pm and then 6:30pm and actually began a quarter of an hour after that. The BBC had cancelled firstCelebrity Mastermind and then Little Mix: The Search (I have no idea, you tell me). Strictly was in serious danger.

“Apologies for disturbing your Saturday evening,” the prime minister began. Like the chummy “Folks,” that opened his message to Tory MPs on Saturday afternoon, it was the wrong note. He had things to tell us, but first, here were the science guys, with the first slide, please.

As we peered at our screens, the words of the scientists were grim

There is an art to the visual representation of complex data. This presentation was to that art as a pre-school finger-painting class is to the National Portrait Gallery. The legends were unreadable and the style kept changing. There were heat maps, there were diagrams that a month ago were yellow, then turned red, and are now largely a red-black shade of the sort that leads doctors to tell you they’re going to have to amputate. As we peered at our screens, the words of the scientists were grim. “Increasing in every area and if we do nothing, the inevitable result is that these numbers would go up,” Chris Whitty, the chief medical officer, said. “Deaths would follow,” Patrick Vallance, the chief scientific adviser, added.

“No responsible prime minister can ignore the message of these figures,” Johnson said. More relevant to our situation is what an irresponsible prime minister would do, and it turned out that he wasn’t going to ignore it, either.

“Now is the time to act,” he said. Well, possibly, given how things have worked out, several weeks ago was the time to act, but who could have known that, except for all the people who were saying it to him, privately and publicly, and anyone who was watching what was happening in other countries, or indeed in this country? Apart from them, who could have known?

Labour had wanted a two-week lockdown, but Johnson, who knows that in politics you always have to go one better than your opponent, is giving us a four-week one. We have to stay in our homes except for exercise, essential shopping, essential work or, in an interesting addition to the list from earlier in the year, “to escape injury or harm.” This is presumably the Dominic Cummings clause, a get-out for when the prime minister’s chief aide is revealed to have hosted a 500-person Bonfire Night rave, in order to check his hearing. Any parent would do the same.

The questions were all on a theme: why had they waited so long? Johnson’s answer was that he was trying to balance “lives and livelihoods”. But by waiting, he had been forced to go for a longer lockdown, so he’d jeopardised both.

Around this point, Rishi Sunak, ever keen to let us know that other politicians are available, released another of his snazzy social media images. “WE STAND TOGETHER,” it bellowed, in front of a fluttering Union Jack. Other politicians are available, and some of them know how to do decent graphics.

Whitty and Vallance wanted us to know it wasn’t all gloom. “There are now multiple shots on goal from the science,” Whitty said. Maybe, but at the other end of the pitch, the defending has been woeful.

Johnson seemed aware of how diminished his currency is. He wanted to close, as he always does, on an upbeat note. “I just repeat,” he said, those “rays of sunshine of optimism – from our scientific advisers, not from me.” Not from you, no. Not tonight.