This is professor Hugh Montgomery, director of the Center for Human Health and Performance at University College London.
On Channel 4's Coronavirus: How to Isolate Yourself, which aired on Sunday, he gave an absolutely perfect explanation of why you should stay at home.
Normal flu, if I get that, it's going to infect, on average, about 1.3, 1.4 people. OK? If there was such a division. And if those 1.3, 1.4 people gave it to the next lot, that's the second time it gets passed on. By the time that happens 10 times, I've been responsible for about 14 cases of flu. This coronavirus is very, very infectious, so every person passes it to three. Now that doesn't sound like much of a difference, but if each of those three passes it to three, and that happens at 10 layers, I have been responsible for infecting 59,000 people.
Now, most people are going to feel a bit pokey or not very pokey and be just fine, but they will have spread it around. And a few will get sick at about day 10 of their illness. So they will need to come to a hospital. When they're in a hospital they will consume resources and time, and people will look after them quite rightly. And they will be monitored to see if they will become really, really sick. Those people then come to an intensive care unit. And that's where, if you're critically ill, your life gets saved or not.
And this is the issue. If we've got a limited resource which we have, a limited number of ventilators, a limited number of doctors, a limited umber of nurses, which is fine because we can't run ourselves with a huge excess capacity all the time, if we overwhelm that, we can't provide that service of caring for these people properly.
...I'm not going to play it down. It's going to be ugly, it's going to be horrible for a large number of people, but it will be a small number of people who get properly sick, and a smaller number again that come to an intensive care unit, and we can save the lives of a large number of those people too.
But please, just remember, the best chance we can give to the people who do fall ill, is if we've got enough beds, and enough staff, and enough kit to be able to be there for you — and if you are irresponsible enough to think that you don't mind if you don't get the flu, remember it's not about you, it's about everybody else.
Or, if you'd like a visual represenation of that:
In a press conference on Sunday, Boris Johnson stopped short of introducing tougher measures to keep people at home, instead issuing another plea to people to follow the official advice on social distancing.