Very few of us alive thought we would ever hear a prime minister of the United Kingdom, with its centuries old liberties, order us to stay in our homes, and only venture out, and never in groups, to acquire what we need to stay alive or for basic essential exercise – on pain if we disobey of being arrested and fined by the police.

His reason, that won’t have escaped you (I hope), is rarely in our history have we faced such a threat to the lives of those we hold most precious as that posed by Covid19. And never in its 72-year existence has the NHS teetered so precariously close to collapse, because of the demands it faces from those with the virus who are struggling for air.

Boris Johnson felt he had no choice, because not enough of us obeyed his initial less binding instructions to avoid social contact. So he is already hearing cries for help from London hospitals, when we are still weeks away from the likely worst point of this crisis.

That dreadful cliche of politics, ‘we’re in this together’, is quite literally true. We either respond as a mutually supporting community or we’re in deep trouble.

And yes, apart from the inconvenience, there will be a price to our prosperity. It is now clear that the immediate reduction in our national income may well be greater even than anything experienced in the Great Depression (in the US and Germany there are respectable forecasts of their national income falling by between a quarter and half on an annualised basis in the coming months).

But failure to act decisively now would levy a much bigger toll, namely deaths and suffering on a scale that no civilised society could tolerate, and who knows what long-term damage to confidence in the foundations of the way we live.

Robert Peston is ITV’s Political Editor. This article originally appeared on his ITV News blog