The United Kingdom's death toll from the novel coronavirus outbreak has passed 12,000 as concern grows about the number of fatalities occurring away from hospitals and being excluded from the daily figures, and a warning was issued about the outbreak's potentially devastating economic impact.

Figures released on Tuesday revealed that a further 778 patients with coronavirus had died in UK hospitals during the previous 24 hours, taking the nationwide total to 12,107.

But information released earlier in the day by the Office for National Statistics, or ONS, suggested the real number is considerably higher, as this total only includes deaths in hospitals.

In some European countries, it has been reported that almost half the recorded deaths from COVID-19 have been in care homes. On Monday, 92 care homes reported outbreaks in just 24 hours.

England's chief medical officer, Chris Whitty, has said more testing needs to take place at care homes and Labour leader Keir Starmer echoed his comments, saying "care homes are on the front line of this crisis".

"The government should include those who sadly die in care homes in their daily reporting numbers and ensure that all care staff have the protective equipment they need."

The outbreak is also putting severe strain on nursing resources. The Press Association reported that as many as one in 10 hospital nurses in England is currently off work because of the novel coronavirus.

Figures seen by the Health Service Journal at the weekend show that there were 28,063 COVID-19-related absences reported among nursing staff and midwives.

This does not necessarily mean that many people have the virus, it also includes those who are isolating because someone in their house is unwell, increasing the pressure on government to organize better testing for key workers.

The outbreak has also contributed to an unseasonal rise in deaths, after the ONS showed that the virus was mentioned on 3,475 death certificates in the week ending April 3 — more than one in five deaths that occurred in England and Wales.

It pushed the weekly death toll above 16,000, which is 6,000 more than usual for this time of year, when death rates usually slow down as winter comes to a close.

Alarm has been expressed after the Office for Budgetary Responsibility, or OBR, which provides independent analysis of the public finances, published a scenario which said the long-term consequences of the outbreak could potentially result in the UK's biggest economic downturn of the last 100 years.

One of Britain's most high-profile political journalists, ITV correspondent Robert Peston, tweeted "the negative numbers it publishes are so big as to induce vertigo", and speaking at the daily Downing Street media briefing, Chancellor of the Exchequer Rishi Sunak pulled no punches about the figures.

"These are tough times and there will be more to come," he said. "The government will not be able to protect every UK business and every household during the COVID-19 pandemic."

The OBR was at pains to point out that this was an "illustrative scenario", not a forecast, more of a hypothetical scenario about what could happen, based on a three-month lockdown. "As we have no way of knowing how long the most stringent public health restrictions might last", the OBR said in a statement.

Unemployment could rise by as many as two million, with GDP for the year falling by 13 percent.

Were the shutdown to be longer or shorter, it added, the figures would be different. "Needless to say there will be considerable uncertainty around any quantitative estimates of this sort," the statement added.

The chief economist of the International Monetary Fund has added to the air of economic gloom with a warning that the worst economic slump since the Great Depression could be on its way.

Gita Gopinath said the world economy is expected to shrink by 3 percent this year, and although there was hope it may bounce back next year, "much worse growth outcomes are possible and maybe even likely".

In Europe, Austria has become one of the first countries to ease restrictions on businesses opening, caused by lockdown measures.

Tight rules about social distancing remain in place, but small shops, home improvement and gardening stores are being allowed to re-open.

A limited number of businesses in Italy, including bookshops and places selling children's clothing, have also been allowed to re-open, subject to strict guidelines.

The country has seen more than 20,000 deaths so far, particularly concentrated in the northern region of Lombardy, where local authorities have chosen to keep restrictive measures in place for some time yet.

Romania's President Laus Iohannis has announced a month-long extension to his nation's lockdown measures. So far Romania has seen almost 7,000 reported cases of novel coronavirus, with 346 deaths, and he said "the danger hasn't passed".

"Relaxing restrictions (...) would lead to a drastic increase in new cases and pressure on the healthcare system."

A court in the French town of Nanterre has ordered retail giant Amazon to conduct risk evaluation at its warehouses to ensure workers' safety is maintained, and until that is done, the company has been told it can only distribute essential items such as medical supplies and food products, or run the risk of a daily fine of one million Euros ($1.1 million).

Also in France, the world cycling's most prestigious race, the Tour de France, looks set to become the latest high-profile event canceled by the outbreak.

It was due to take place from June 27 to July 19 but President Emmanuel Macron's announcement that public events remain subject to restrictions until mid-July mean it looks destined to be scrapped this year.