When will we wake up to the sobering reality?

The official guidance to intensive care doctors detailing the process for deciding who should receive critical care if rationing is required makes for sobering reading.

It was published on the website of the National Institute for Health and Care Excellence (Nice) in the early hours of yesterday.

It came at the end of a bright spring day in which thousands crowded city parks, farmers’ markets and seaside promenades despite government pleas for social distancing. Perhaps we Brits do not grasp the fearful logic of the coronavirus’s exponential growth. Or perhaps we’re just not up for quarantine. Either way, this weekend may be looked back on as a reckless nation’s last roll of the dice before the storm hit.

For make no mistake, the mathematical modelling shows we are in lockstep with Italy’s terrible trajectory, lagging just two weeks behind. Inigo Martincorena, group leader at the Sanger Institute in Cambridge, posted an analysis at the weekend which shows Britain’s numbers almost mirror Italy’s in terms of Covid-19 cases and deaths.

He warned that unless Britain was completely locked down by today, we would suffer the same fate or worse. “You can see how the UK epidemic is closely following Italy’s, with a 14- to 15-day lag and the same doubling rate. We need a national lockdown by Monday just to be as badly hit as Italy. Time is running out.”

The Prime Minister and other UK politicians have been presented with the same data and yesterday appealed again for people to stay at home.

“Life has changed, we’ve got to do things differently for a while now,” Sadiq Khan, the London mayor, told the BBC. “Social interaction leads to the disease spreading, leads to people dying. Don’t leave your home unless you really, really have to.”

He added: “Don’t just do it for yourself, do it to stop the disease spreading, do it for your vulnerable loved ones who will die if you don’t, do it for the heroic NHS who need our help.”

If the Nice guidance on the allocation of critical care beds (with ventilators) does not alter our behaviour, it’s hard to know what might. It makes coldly stark the life-and-death choices doctors are likely to face.

The guidance provides an “algorithm” to help them decide who should be admitted to these scarce facilities and who should not.

In Italy there has been controversy as doctors have been forced to discriminate between patients largely on age. And this, in a country which has twice the number of critical care beds than we have – 14 per 100,000 people, compared to the UK’S seven.

The Nice guidance does not categorise UK Covid-19 patients by age but instead asks doctors to rank patients on a nine-point “clinical frailty scale”. At one end of the scale, with a score of one, are the “very fit”. At the other end, with a score of nine, are the “terminally ill”. The scale is reproduced left. How do you score?

Those with a score of less than five are considered fit enough to benefit from critical care, subject to consideration of underlying conditions and the severity of their illness. For those scoring over five, doctors must decide if critical care is “appropriate”.

For patients with confirmed Covid-19, decisions about admission to critical care should be made on the basis of “medical benefit, taking into account the likelihood that the person will recover … and within a period of time consistent with the diagnosis,”

‘The UK epidemic is closely following Italy’s … We need a national lockdown by Monday just to be as badly hit as Italy. Time is running out’

says Nice. The guidance also provides doctors with mortality data for patients suffering from pneumonia, the main form of severe illness caused by Covid-19. These data are banded by age, as are similar mortality tables for patients with underlying heart and lung conditions. These additional data will help inform doctors’ judgments beyond the patient’s basic frailty score.

It is not just in Italy where critical care units are being overwhelmed.

A friend in Barcelona told me he worried Britain would only lockdown fully once footage of UK hospitals in crisis hit the television news. He said the rules in Spain were initially taken lightly but the “sheer speed” at which deaths mounted changed that.

“Over here it is deadly serious now. No one is mucking about. If you go out it must be quick and for something important,” he said.

Expect those television images any time now.

On Thursday night, a major London hospital declared a “critical incident” due to a surge in patients with coronavirus. “This means that we currently do not have enough space for patients requiring critical care,” said Northwick Park Hospital in Harrow in a message to staff.

The hospital has since found additional capacity. Nevertheless, a relentless pressure is building, with cases in the UK doubling roughly every few days.

A senior director at another London acute trust told the Health Service Journal: “Given we’re in the low foothills of this virus, this is f-----petrifying.” He added: “The trusts in outer London seem to be hit much worse at the moment, probably about two weeks ahead of the rest of the country. I was in denial about the seriousness of this virus a couple of weeks ago, but not anymore … things are going completely nuts.”

Britain has a similar population size to Italy and although Italy has a higher proportion over 65, the difference is not huge, 18.1 per cent versus 21.5. However, the incidence of adult obesity in Britain (a good marker for underlying conditions including heart disease and diabetes) is much higher, 27.8 per cent compared to 19.9 in Italy.

Official figures yesterday brought the total tally of Covid-19 deaths in Britain to 281. In Italy, deaths stand at 5,476. This may feel much further ahead than a mere 14 days but only if you ignore exponential growth.

To picture that better, experts recommend we try the “wheat and chessboard” test. Imagine putting one grain of wheat on the first square of a chessboard, two on the second, four on the third and then continue doubling until all 64 squares are covered. Now, ask yourself, how many grains of wheat are there?

The answer is 18,446,744,073,709, 551,615 (18.4 quintillion) – much more than most of us would expect.