Emergency field hospitals set up in England to treat patients with Covid-19 are to close due to the fall in patient numbers, the government said on Tuesday.

Seven "Nightingale" hospitals were opened with fanfare during the first wave of the virus last year and the government has put their total cost at £532 million ($738 million, 620 million euros).

They were designed to provide extra beds for patients and ease capacity on the wider health system but have not been widely used.

Health Secretary Matt Hancock said numbers in hospital with Covid-19 are now under 10,000, down from a peak of almost 40,000 in January.

"We're now in a position to stand down our Nightingale hospitals," he added.

Hancock hailed the development as an "important moment in our national recovery".

More than 22 million people have now received a Covid vaccine, and daily case numbers and deaths are falling.

Bosses in the state-run National Health Service (NHS) said the hospitals would close from April, but two would stay open as vaccination centres.

Named after one of the pioneers of nursing, Florence Nightingale, some are in exhibition centres. 

The facilities offered thousands of beds but have not treated the bulk of patients, as standard hospitals adapted to a surge in cases better than expected. 

Staffing the vast field hospitals has also been a problem.

One such hospital in a convention centre in Yorkshire in northern England never treated a single patient, the BBC reported Monday.

Hancock nevertheless hailed the hospitals, calling them "monuments to this nation's ability to get things done fast when it really matters."

He said they "played a critical role" and "gave confidence" that the NHS could continue to provide care during the pandemic.

The UK has had more than four million virus cases and 124,566 deaths, the highest figure in Europe but its vaccination rollout has been among the world's fastest.