At the beginning, the illness isn’t too bad, some coughing and a weird furriness round my lungs. I’ve also lost the willpower to do anything at all. But then, I’m thinking, that can be quite nice. At this stage, I’m looking forward to what you might call a platonic illness: lots of black-and-white war films in the afternoons with Noël Coward in white shorts, pretending to be Lord Mountbatten rallying the men and shooting at submarines, while my wife Nicole brings me hot lemon, honey and ginger.

My GP has begun to FaceTime me twice a day, though he says he can tell much more from my voice than from my appearance. Because I am confused by the mildness of the onset, I say to him: ‘Maybe I haven’t got it.’ He replies darkly: ‘Oh, you’ve got it.’

But the question is: what have I got?

A third of the patients admitted to hospital with Covid-19 die. And half of those admitted to intensive care don’t make it. But what exactly are they dying of? This question isn’t as simple as it seems. The rush to put people on ventilators is already slowing. With this disease, ventilators aren’t doing the job they’re meant to do. Blood is coming into the lungs without much oxygen, and then it’s leaving without much oxygen. What’s the point? And people are having to stay on ventilators far longer than normal.

Doctors are becoming aware that a lot of people who go on ventilators may never come off.

In fact, Covid-19 seems to be a sort of dirty bomb, thrown into the body to cause havoc. A lot of patients are actually dying of kidney failure. There’s muscle inflammation in nearly everybody. In some cases, patients are delirious or suffering inflammation of the brain. But all this is less pervasive than the blood clotting.

Beverley Hunt, a professor of thrombosis – I didn’t know there was such a thing – at King’s College London, is telling us that she’s noticed an awful lot of sticky blood. In fact, she’s seeing the stickiest blood of her career. ‘And when you’ve got sticky blood,’ she says, ‘you’re much more prone to having deep vein thrombosis and pulmonary embolism, which is when one of the deep vein thromboses travels around and blocks the blood supply to the lungs, which adds to the problem of pneumonia.’

Professor Hunt uses an unexpected phrase: ‘It’s almost medieval in what we’re seeing.’

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