The UK’s hospitals are facing a more acute crisis than in the first Covid-19 wave in the spring with many more patients being treated for the virus and, despite the national lockdown, only the faintest glimmers of hope emerge from the latest data that relief might be imminent.

With the NHS struggling, Chris Whitty, England’s chief medical officer, took to the airwaves on Monday to warn that the country was entering the “most dangerous” part of the pandemic and that the “next few weeks are going to be the worst” for the health service.

UK hospitals are some of the fullest in Europe with Covid-19 patients and the authorities’ fear is that, as they fill up further, the quality of care declines, triaging gets stricter and more people die.

The medical officer issued his stark warning because the pathway towards a health emergency from the virus is now well understood. It starts with rising infection rates for the over-60s, progresses to more hospital admissions, then beds fill up, followed by greater use of ventilators and finally more deaths.

There are significant lags in this process, so most of those who are dying from Covid-19 now were infected before Christmas: an intensifying NHS crisis and higher death rates are therefore all but inevitable.

One of the most worrying signs is that as the new, more transmissible variant of coronavirus, first publicly recognised by the government on December 14, becomes the dominant strain, infection rates among older people are continuing to rise.

Line chart of weekly positive Covid-19 cases per 100,000 people showing Infection rates for over 60s have jumped since early December

Across England, case rates for the over-60s, who are most likely to be hospitalised, have more than quadrupled since early December. Although the weekly rate dipped marginally in the most recent data, it was still too early to be called an improving trend, prompting Prof Whitty to urge people to avoid unnecessary contacts.

Infection rates have led to a sharp increase in hospital admissions. In England, the daily number of admissions also quadrupled from early December, peaking on January 6 at 3,967.

Line chart of Covid-19 hospital admissions in England showing daily Covid-19 hospital admissions quadrupled since early December

A drop in the two days after that date was “promising news”, according to Oliver Johnson, director of the Institute for Statistical Science at Bristol university, but also too early to be called a trend.

The problem for hospitals, he added, was that until discharges, which would include deaths, surpassed admissions the number of coronavirus patients in hospitals would continue to rise.

“It may need admissions to fall to the levels of a week or more ago before the total number of beds occupied starts to fall,” Prof Johnson said.

In most NHS regions, hospitals are struggling to cope with this trend and the number of occupied beds is already higher than at the worst point of the spring Covid-19 epidemic.

Chart showing that Covid-19 hospital occupancy is high and rising again in most of the UK, surpassing the spring peak in most areas

In England, the number of people in hospitals with coronavirus is rising at a rate that will be double the peak of the first wave by the end of this weekend.

As the condition of some of the hospitalised patients deteriorates, the demand on intensive care increases, with occupancy rates far above normal levels, as does the demand for mechanical ventilation. This was almost as high on January 9 — at 2,860 people in England — as it was at the spring peak of 2,881 on April 12.

Some hospitals, such as Southend, have started to limit the oxygen available to patients to manage limited supplies, the BBC reported, with managers saying they were “working to manage” a difficult situation.

While the UK is far from alone in having a serious health emergency, the rise of the new strain of Covid-19 has put a greater pressure on hospitals in recent days than in most advanced nations.

Chart showing that UK’s Covid hospital occupancy is now among the highest in the world

Bed occupancy is rising towards the highest in Europe with 50 out of every 100,000 people in the population in hospital with coronavirus and a weekly rate of new admissions rising to 30 per 100,000.

International data show that the equivalent weekly rate of admissions per 100,000 is only 17 in Denmark, which is high in Europe, 11 in France and nine in the US.

Even though the picture in hospitals emerging from the data is dire, Prof Whitty predicted it would deteriorate further, with vaccinations not likely to have a significant effect in relieving the pressure for many weeks.

The UK, he said, was “not anywhere near” achieving herd immunity through vaccination yet.