Boris Johnson will hold a news conference later as the government considers a new month-long lockdown across England.
The hope is that stricter measures could then be eased by Christmas.
It comes as documents seen by the BBC suggest the UK is on course for a much higher death toll than during the first wave unless further restrictions are introduced.
Deaths could reach more than 4,000 a day, one of the models suggests.
That figure is based on no policies being brought in to slow the spread of the disease, but most of the models peak at about 2,000 a day.
The prime minister will be joined by England’s chief medical officer Chris Whitty and the government’s chief scientific adviser Sir Patrick Vallance for the briefing, following a cabinet meeting to discuss the government’s coronavirus response.
The news conference was originally scheduled for 16:00 GMT but is now due to take place an hour later at 17:00.
It is expected schools, colleges and universities would stay open under any new “stay at home” order.