Travel restrictions are to be immediately imposed in the United Kingdom as a result.
A second new variant of the coronavirus has been discovered in South Africa, UK Health Minister Matt Hancock has confirmed.
Flights from South Africa to the UK have now been stopped. Hancock added that anyone who has been there, in the last fortnight, must quarantine immediately - without coming into contact with anyone at all.
Hancock also confirmed that further restrictions in the UK are to be introduced from St. Stephen's Day.
Essex, Norfolk, Sussex, Surrey, Cambridgeshire, Oxfordshire and Hampshire will join London and the south east in Tier 4 from Saturday onwards, Hancock announced.
At a press conference on Wednesday afternoon, Hancock said cases had risen "57% across the country in the last week," leaving him no choice but to impose more severe restrictions across England.
"We simply cannot have the Christmas that we all yearn for," he said, calling on the people of Britain to ''minimise their social contact as much as is possible" over the Christmas period.
When the tier system was first introduced, Cornwall, the Isle of Wight and the Scilly Isles were the only regions in Tier 1, with the most relaxed restrictions. From 26 December onwards, nowhere in England will be in Tier 1.
The following areas will move from Tier 2 into Tier 3:
- Bristol
- Gloucestershire
- Somerset including North Somerset council area
- Swindon
- Isle of Wight
- New Forest
- Northamptonshire
- Cheshire
- Warrington
