Nicola Sturgeon has warned Scots to prepare for a swathe of new nationwide lockdown restrictions next week as a "circuit break" to stop the resurgence of coronavirus.
The First Minister said "hard but necessary" decisions may be needed in the coming days to prevent a second full lockdown and the country is at "probably the most critical point" since the first one was imposed in late March.
She said she would decide the next steps for Scotland over the weekend and disclosed she had asked the Prime Minister to convene a Cobra meeting for a UK-wide discussion.
Both Ms Sturgeon and Boris Johnson are considering a 'circuit breaker' plan, which would see curfews and restrictions on activities for at least a fortnight and probably longer.
Although not as draconian as a full lockdown, it is hoped the move would have a sharp impact on breaking the chain of transmission and stopping the recent surge in cases.
Pubs and restaurants could be ordered to close altogether or have their hours severely restricted but schools would remain open. Shops and non-essential workplaces may also not be forced to close again.
This from @devisridhar is important. If we need to tighten restrictions, it will be in the interests of trying to keep the virus under control while avoiding another full scale lockdown - and crucially keeping children in education https://t.co/OAyqUj9Mdp— Nicola Sturgeon (@NicolaSturgeon) September 18, 2020
Speaking at her daily briefing, Ms Sturgeon said that "whether you call it a circuit breaker or a fire breaker...that is the kind of thing that I think we’re all thinking about just now."
She said that all four home nations were facing "broadly the same challenge" and argued the key question was "how do we act quickly, early, decisively to stop a deteriorating situation getting worse and instead really push it back, or to the right track again?"
The First Minister also urged Scots not to cross the border to visit the North East of England, where major curbs have already been introduced, and for people from those areas to stay out of Scotland.
Her warning came as she disclosed 203 more Scottish cases had been recorded in the preceding 24 hours and another death.
Ms Sturgeon said the proportion of tests coming back positive had risen to 4.4 per cent - just below the World Health Organisation's five per cent threshold for the virus no longer being under control.
The R number - the average number of people each carrier infects - is estimated to be above one and as high as 1.4 in Scotland. This compared to between one and 1.2 across the UK.
While relatively few "older, more vulnerable people" have contracted the virus in recent weeks, the First Minister warned "that picture is also beginning to change."
In late June Ms Sturgeon said Scotland was "not far away" from eliminating Covid-19 but the number of cases has since surged to the highest level since the start of May.
She said Scotland is now "broadly" four weeks behind France and urgent action must be taken so "we don't end up where they are now", with around 10,000 cases a day and hundreds of people in intensive care.
This is a very serious moment. Coronavirus is accelerating. We will do what it takes to keep people safe. pic.twitter.com/rTiDax1FA6— Matt Hancock (@MattHancock) September 18, 2020
More than 1.75 million people in the west of Scotland are already barred from visiting other households following a spike in cases linked to indoor family gatherings and house parties.
But cases have continued to increase nationally despite Ms Sturgeon issuing a new edict limiting all gatherings to six people, excluding the under-12s, and two households.
The First Minister said: "First and foremost, we need to act to interrupt that exponential growth. No one wants to see another full-scale lockdown."
She added: "So, I am today giving the nation advance notice, that the coming days are likely to see some hard but necessary decisions."
Ms Sturgeon warned "doing nothing almost certainly isn’t an option" and the good news is "we do still have time to prevent" a second full lockdown.
Warning this weekend will be "critical", she said: "Do we need to have more national restrictions? These are the decisions that we will be pondering and trying to come to conclusions on over the next few days."
Asked how long any 'circuit break' measures would have to last, she added: "It can take a period of weeks to know whether something you start doing today has an effect."
Jason Leitch, Scotland's national clinical director, also warned that nationwide restrictions must be considered to stop the virus as "now we are beginning to see it everywhere - the fires are beginning to light."
Around two million people in the North East of England up to the Scottish border, including Newcastle, County Durham and Northumberland, were banned on Thursday from meeting people from outside their households. Restaurants and pubs in the area must shut at 10pm.
Ms Sturgeon said Scots should not travel to areas that are under restrictions and people in the North East of England "shouldn't come to other parts of the UK."
Mark Woolhouse, professor of infectious disease epidemiology at the University of Edinburgh, said an "optimistic" aim of 'circuit break' restrictions could be to drive down the R number and reduce the incidence of new infections by half for a short period.
After two weeks the rate of new cases would be expected to increase again, he warned, but it would take time to return to the level seen before measures were introduced.
He said: "The expectation is that all this will buy several weeks of time which could be used, for example, to improve the performance of the test, trace and isolate system."