Video report by ITV News Political Correspondent Paul Brand
Self-isolation periods have been increased from seven to 10 days for anyone in the UK with coronavirus symptoms or a positive Covid-19 test result, the government has announced as it seeks to avoid a second wave.
Health Secretary Matt Hancock told ITV News a second wave of coronavirus is "coming across Europe" and said the policy change on isolation periods had been made to "prevent" similar spikes in the UK.
He said there was evidence of cases "rising sharply" in some countries on the continent.
"We want to prevent that from happening here so we're prepared to take action, sometimes quite quickly as we had to, sadly, with people were in Spain in terms of quarantine.
Hancock on 'Europe's second wave':
"We're prepared to take that action to keep people here safe."
Prime Minister Boris Johnson reiterated the message, saying there is currently "resurgence of the virus in some other European countries".
During a visit to North Yorkshire, Mr Johnson added: “It’s absolutely vital as a country that we continue to keep our focus and our discipline and that we don’t delude ourselves that somehow we’re out of the woods or that this is all over, because it isn’t all over.”
He suggested more places could follow Leicester in seeing a return to lockdown after a spike in the area's coronavirus cases was brought down by a tightening of restrictions.
He said there are "between 10 and 30 places where you are seeing it bubbling up a little bit" and the best way to deal with spikes was with "tough, swift and decisive local lockdowns".
England's deputy chief medical officer Professor Jonathan Van-Tam said the change to isolation periods was being made due to the “low but real possibility of infectiousness” between seven and 10 days after the onset of the illness.
Anyone currently self-isolating who may be nearing the end of their seven days - for example on day six of isolation - will now need to stay inside until they have reached 10 days.
A joint statement on behalf of all UK nations admitted the evidence was "still limited" that people were still infectious when they are "mildly ill and are recovering" but said it had "strengthened".
The statement, co-signed by Professor Chris Whitty, Dr Frank Atherton, Dr Gregor Smith and Dr Michael McBride, added: "We have considered how best to target interventions to reduce risk to the general population and consider that at this point in the epidemic, with widespread and rapid testing available and considering the relaxation of other measures, it is now the correct balance of risk to extend the self-isolation period from 7 to 10 days for those in the community who have symptoms or a positive test result."
The rule change is "particularly important" in protecting those who have been shielding and "in advance of the autumn and winter when we may see increased community transmission".
Health Secretary Matt Hancock told ITV News his "critical message" to anyone with symptoms was to "get a test - it's so important that people do - and then follow the medical advice".
He explained the change of policy, saying the scientific advice is "constantly" updating "and when the scientific changes...then we are guided by that science".
"When the facts change then of course we update our policy," he added.
He said the government was taking a "precautionary approach" to coronavirus by increasing the isolation period.
Later, giving a speech to the Royal College of Physicians, Mr Hancock said the coronavirus pandemic had been "as close as you can get to fighting a war without actually fighting a war".
He admitted "we haven’t got everything right and that there will be lessons that we need to learn from this pandemic".
Hancock admits mistakes have been made during crisis:
Continuing the theme of battle, he said: "We can see a second wave emerging in Europe and we will do everything in our power to stop it reaching our shores."
Labour's shadow education secretary Kate Green said she was not only concerned about spikes in Europe, but about case rises in the UK.
"It's certainly worrying to see a rise in cases in countries that had previously seen them reducing and I think we're possibly beginning to see a small rise happening here too.
"So I think there are real concerns that as lockdown restrictions have been eased, people are mixing more socially that that is a good breeding ground for the virus and we have to be very, very vigilant."
Hancock compares coronavirus pandemic to war:
Mr Hancock said there would be no changes in the next few days to quarantine rules for people returning from overseas, including Spain, but said work was ongoing to reduce the period of isolation.
He said scientists were assessing whether testing people during the 14-day quarantine period would mean it was safe to release them earlier.
“This is a really important, essentially scientific clinical question, so that’s something that we’re working on,” he told the BBC.
“But we are not imminently making an announcement on it because that work is not concluded, and until it is absolutely safe to make that sort of change, then we won’t do so, but it is something that we’re working on.”
Hancock on why advice was updated
The “big scientific challenge” with testing people at the border was that you “can incubate this disease for many days without displaying any symptoms, and that wouldn’t show up in a test”.
He added: “So if people get off a plane coming from somewhere that has a high degree of disease and therefore they have to quarantine, if you get the test, and the test result comes back negative, you could still have the disease, you’re just incubating it.”
Mr Hancock said he was not against testing people at the border but more work was needed on the timing of Covid-19 tests to make them effective.