Huntingdonshire will now move into Tier 4 from 00.01 on Boxing Day.
In an announcement on the BBC this afternoon (Wednesday), Health and Social Care Secretary Matt Hancock said the changes were "necessary to control the virus".
Huntingdonshire will join Peterborough and neighbouring Hertfordshire which were already in the highest tier after an announcement on Saturday.
This means a return to the spring lockdown restrictions which mean all but essential retail must close and people cannot travel in or out of the area.
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