Suffolk and the whole of Essex will be placed into Tier 4 coronavirus measures from Boxing Day, the government has announced.
Health secretary and West Suffolk MP Matt Hancock led a government briefing on Wednesday afternoon, where he revealed Covid-19 cases had risen "sharply" in East Anglia, as well as other parts of the south-east of England.
He said it was "absolutely vital" that action is taken as case numbers escalate due to a new, mutated form of the virus.
Suffolk leaders have said the move was "inevitable" as case numbers continue to rise in the county.
The new measures come into effect at 00.01am on Boxing Day, Mr Hancock said, with the current Christmas Day rules on household mixing allowed to continue.
Suffolk and the Essex districts of Colchester, Tendring and Uttlesford were left in Tier 2 after the government's review of the system last week.
The rest of Essex is already in Tier 4 measures.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here