The UK's COVID-19 alert level has been moved from level three to level four, meaning transmission of the virus is high or rising exponentially.
The chief medical officers of England, Scotland, Wales and Northern Ireland recommended upgrading the measure to the second-highest level due to a "rapidly" rising number of cases.
The COVID-19 alert level had previously been at four during the peak of the pandemic earlier this year, before being moved down to three in the middle of June following a steady decrease in the number of coronavirus infections.
Announcing the decision to move the alert level back up, the chief medical officers said in a statement: "The CMOs for England, Scotland, Wales and Northern Ireland have reviewed the evidence and recommend all four nations of the UK should move to level 4.
"After a period of lower COVID cases and deaths, the number of cases are now rising rapidly and probably exponentially in significant parts of all four nations.
"If we are to avoid significant excess deaths and exceptional pressure in the NHS and other health services over the autumn and winter everyone has to follow the social distancing guidance, wear face coverings correctly and wash their hands regularly.
"We know this will be a concerning news for many people; please follow the rules, look after each other and together we will get through this."
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The chief medical officers took the action after a recommendation by the government's Joint Biosecurity Centre.
Health Secretary Matt Hancock said: "The raising of the alert level announced by the UK chief medical officers reflects the significant shift in the current threat posed by coronavirus.
"This country now faces a tipping point in its response and it is vital everybody plays their part now to stop the spread of the virus and protect lives.
"The first line of defence has always been all of us playing our part, remembering hands, face and space, the rule of six and self-isolation of those who risk passing on the virus."
Prime Minister Boris Johnson announced the creation of the Joint Biosecurity Centre – and a five-tier alert system to rank the threat from coronavirus – in May this year.
The alert level system is similar to that used for the threat from terrorism in the UK.
The five levels are:
Level 5 – The highest on the scale, this indicates there is a "material risk" of the NHS being overwhelmed.
Level 4 – This means the COVID-19 epidemic "is in general circulation" and the "transmission is high or rising exponentially".
Level 3 – While this level also suggests the epidemic is "in general circulation", it omits the statement "transmission is high or rising exponentially". The alert level was lowered to level three in June and came amid the relaxation of some COVID-19 restrictions.
Level 2 – To shift to this level, the government guidance says the virus would be present in the UK, but that the number of cases and transmission is low. It says this would then allow "no or minimal social-distancing measures", but with enhanced "testing, tracing, monitoring and screening".
Level 1 – This would indicate "COVID-19 is not known to be present in the UK". The guidance suggests the only action required at this sRead More – Source