Video report by ITV News Health Editor Emily Morgan
The UK's Covid-19 alert level should be increased to level 4, meaning transmission of the virus is “high or rising exponentially”, the chief medical officers of England, Wales, Scotland and Northern Ireland have said.
In a joint statement that all four nations of the UK should move from level 3 on the recommendation of the Joint Biosecurity Centre as cases rises sharply across the nation
They said: "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 concerning news for many people; please follow the rules, look after each other and together we will get through this."
In response Health Secretary, Matt Hancock said the joint statement reflected a "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.”
The move comes after the government's top scientists painted a grim picture of the UK's battle with coronavirus, with the chief scientific adviser Sir Patrick Vallance warning that UK could see 50,000 new coronavirus infections every day by mid-October if restrictions don't cause rates to fall.
That case rate would likely translate into 200 deaths each day a month later, he said.
Sir Patrick said the infection rate could be brought down if everyone follows the rules which are already in place - such as the rule of six - but suggested the restrictions could soon be tightened.
Boris Johnson's spokesman echoed this, saying the PM was speaking to the first ministers of Wales, Scotland and Northern Ireland on Monday before announcing any changes.
Mr Johnson will make an announcement on Tuesday after chairing an emergency Cobra meeting on the morning.
Sir Patrick Vallance spoke of progress in the vaccination programme, ITV News Health Editor Emily Morgan explains
On restrictions, Sir Patrick said: "There are already things in place which are expected to slow that, and to make sure that we do not enter this exponential growth and end up with the problems that you would predict as a result of that.
"That requires speed, it requires action and it requires enough in order to be able to bring that down."
Speaking alongside Sir Patrick, Chief Medical Officer, Professor Chris Whitty, said everyone should follow all restrictions, even if they do not consider themselves vulnerable to the virus, because higher prevalence in the young, for example, is likely to translate into increased infections among the elderly - the group considered most at risk.
"You cannot in an epidemic just take your own risk, unfortunately you’re taking a risk on behalf of everybody else," he said.
"So, this is not someone else's problem, this is all of our problem," he added.
At the press conference - the first they have held without the company of a politician - the scientists revealed that just 8% of the UK's population is thought to have had the virus.
The scientists said they are trying to asses the best way to "manage the spread of the virus ahead of a very challenging winter period.”
The pair drew on data from other countries such as Spain and France, which are experiencing a second surge, to underline how their experience could be replicated in the UK.
Sir Patrick said in Spain and France "it started with younger people in their 20s and spread gradually to older ages as well".
He said: "That increasing case number has translated into an increase in hospitalisations.
"As the hospitalisations have increased... very sadly, but not unexpectedly, deaths are also increasing."
At the height of the coronavirus pandemic, the UK recorded more than 5,000 daily cases and over 1,000 deaths.
Earlier, Matt Hancock suggested new national restrictions could soon be implemented to combat the rise of coronavirus, with the UK at "tipping point".
The health secretary, speaking to ITV's This Morning, suggested any new measures would focus on social aspects of life, rather than workplaces and education settings.
Asked whether landlords would be told to shut pubs this weekend, Mr Hancock said: "We will be absolutely clear about the changes we need to make in the very, very near future."
Prof Whitty hinted at curbs to social lives being needed to prevent coronavirus spiralling out of control, saying there was a need to "break unnecessary links" between households and a need to "change course".
He said there were four things to do - washing hands and using masks, quarantine measures, and investing in vaccines and drugs.
"The third one, and in many ways the most difficult, is that we have to break unnecessary links between households because that is the way in which this virus is transmitted," he said.
"This is a balance of risk between if we don't do enough the virus will take off - and at the moment that is the path we're clearly on - and if we do not change course we are going to find ourselves in a very difficult problem," he said.
Prof Whitty suggested that science would eventually "ride to our rescue" but "in this period of the next six months, I think we have to realise that we have to take this collectively, very seriously".
Sir Patrick said there is a possibility that small amounts of vaccine could be made available to certain groups of people by the end of the year.
He said there is "good progress being made" on developing a vaccine, adding: "We don't yet know they will work but there is increasing evidence that is pointing in the right direction and it is possible that some vaccine could be available before the end of the year in small amounts for certain groups. "
It is understood he will hold a press conference with the first ministers of Wales, Scotland and Northern Ireland later on Monday.
By Tuesday, around 20% of the UK's population - about 13.5 million people - will be living under increased coronavirus restrictions, when new rules are enforced in parts of England.
It is understood Mr Johnson spent the weekend with senior ministers and advisers discussing what extra action can be taken as the rise in the number of new cases showed no sign of slowing.
Labour's shadow chancellor Anneliese Dodds said the imposition of a new national lockdown would show the government's test and trace regime had failed.
She told ITV News: "I think unfortunately if we do see additional restrictions being imposed it would be a failure of test, trace and isolate.
"We've been saying for many months that the government needs to be open about where the problems are and we've been trying to set out solutions."
Watch the full Prof Whitty-Sir Patrick briefing