The UK's coronavirus alert level should be raised from level three to four, meaning transmission is "high or rising exponentially", its chief medical officers have said.
It comes after the government's scientific adviser warned there could be 50,000 new coronavirus cases a day by mid-October without further action.
The PM will make a statement in the Commons on Tuesday.
On Monday, a further 4,368 daily cases were reported in the UK, up from 3,899.
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