Boris Johnson is set to escalate the country's coronavirus response to the next phase, which will see more people encouraged to stay at home.
The prime minister will chair an emergency COBRA meeting on Thursday where he is expected to declare that the UK will switch from trying to contain COVID-19 to delaying its spread.
This comes the day after the World Health Organisation designated COVID-19 a pandemic.
Moving to the delay phase will mean social distancing measures could be brought in.
People with even the slightest symptoms may be asked to remain at home.
More guidance for over-65s and the vulnerable is expected soon as part of the change to the "delay" phase.
Draconian measures such as mass school closures, banning public gatherings and mass testing of the public are not set to be deployed at this stage, although the government has said they remain an option.
The UK is not copying the drastic action in countries such as Italy, where the entire population has been quarantined and football matches played behind closed doors.
Health Secretary Matt Hancock has told MPs there are "no plans for a mass closure of schools", although individual schools might be told to close.
Speaking in the Commons on Wednesday night, he said: "There are significant downsides [to closing schools] especially because of the knock-on consequences it has on the number of staff available for critical public services, including the NHS and social care."
Until now, the government has been focused on trying to stop coronavirus from being transmitted inside the country.
On Monday, Mr Johnson suggested an escalation was likely - admitting the containment strategy was "extremely unlikely to work on its own".
He went on to say that "extensive preparations" were under way to move to the "delay" phase to slow the virus' spread.
Four phases of UK's response plan:
Now, Mr Johnson is expected to confirm Britain has entered that second stage, without following every suggestion contained in that action plan.
The prime minister is likely to come under pressure to explain why he does not take all the measures in the action plan available during the "delay" phase.
The action plan published last week says of the delay phase: "Action that would be considered could include population distancing strategies, (such as school closures, encouraging greater home working, reducing the number of large scale gatherings) to slow the spread of hte disease throughout the population, whilst ensuring the country's ability to continue to run as normally as possible.
"The UK governments' education departments' planning assumptions include the possibility of having to close educational settings in order to reduce the spread of infection".
Other key coronavirus developments include:
Discussion between ministers and the opposition are also being held about emergency legislation which could be passed next week.
The emergency legislation is likely to give the power to government to relax lots of regulations, including allowing larger class sizes, changes to rules on care homes, allowing retired medical professionals to return to work.
New figures published on Wednesday showed that 460 people now have COVID-19 - a rise of 87 cases in 24 hours.
These "social distancing" tactics are the main tools available try to prevent accelerated transmission when no vaccine is yet available
Meanwhile, Mr Hancock has confirmed parliament will not close, despite health minister Nadine Dorries being diagnosed with COVID-19 and another MP going into self-isolation as a precaution.
The health secretary admitted the House of Commons "may have to function differently" but insisted MPs' ability to create new laws to tackle the outbreak and scrutinise the government was "vital".