LONDON, March 13 (Xinhua) -- The number of confirmed COVID-19 cases in Britain reached 798 Friday, an increase of 208 over 24 hours, according to the British Department of Health and Social Care.
It is by far the highest rise in cases of COVID-19 in a single day. As of Friday morning, a total of 32,771 people have been tested for COVID-19. Of those, 31,973 tested negative. It is also the first time the day-on-day increase has been higher than 200.
Also on Friday, a London Underground driver tested positive for the novel coronavirus and at least 11 MPs were in self-isolation following advice from public health authorities.
According to health authorities, the true figure for people infected with the novel coronavirus in Britain might be between 5,000 and 10,000.
The British government announced Thursday that the country has switched from the "containment" phase to "delay" in response to the spread of virus in the country, a move to encourage more "social distancing" among the Britons.
Earlier Friday, a Foreign Minister spokesperson issued travel advice to Spain, saying that "we are advising against all but essential travel to the regions of Madrid, La Rioja and the municipalities of La Bastida, Vitoria and Miranda de Ebro."
"The travel advice has been updated because these areas have been designated by the Spanish authorities as 'areas of community transmission'," the spokesperson said. "We are not advising those in Spain to leave as transport routes out of the country remain open."
Prime Minister Boris Johnson warned the British public Thursday to prepare to "lose loved ones before their time."
The prime minister described the threat of coronavirus as "the worst public health crisis in a generation," but he would not follow the example of other countries to close schools.
Johnson insisted that his government was being guided by scientific advice, saying closing schools "could do more harm than good."
Patrick Vallance, the British government's chief scientific adviser, said it is hoped that the government's approach to tackling coronavirus will create a "herd immunity" to the disease.
Vallance said some of the social distancing measures put in place by the government, including self-isolating for seven days if symptoms develop, are "actually quite extreme."
He said millions of the British people, around 60 percent, would need to contract the disease to lessen the impact of what is likely to become an "annual virus."
However, Jeremy Hunt, the former British health secretary, called for more aggressive steps, including closing elderly care homes to outside visitors.
Meanwhile, experts criticized the measures as too limited to have a major effect and inadequate given the scale of the looming threat to health.
"I can't see that any of these measures are going to have a big impact...None of that is really going to affect transmission in the UK," Paul Hunter, professor in medicine at the University of East Anglia, was quoted as saying by The Guardian newspaper Friday.
The prime minister is expected to hold talks with world leaders about the international response to the coronavirus outbreak, Downing Street said.
The prime minister's official spokesman said Johnson has spoken to French President Emmanuel Macron and Canadian Prime Minister Justine Trudeau and will be talking to other leaders.
"The prime minister thinks that this crisis affects countries around the globe and it requires a global response," the spokesman added.