Pubs, restaurants and non-essential shops will be forced to close from Boxing Day after Norfolk and Suffolk were moved into the highest tier.
With cases on an upward trajectory and a new variant of the virus spreading, health secretary Matt Hancock announced a raft of tier moves on Wednesday afternoon, with many places moved into higher tiers of restriction.
And Norfolk and Suffolk, which were initially placed in Tier 2, were among them, being escalated to Tier 4, the highest restriction.
It means that pubs and restaurants must close unless offering takeaway or delivery, theatre shows will be brought to a halt and supporters will no longer be able to attend football matches.
What does each tier mean?
Mr Hancock said: "It is absolutely vital that we act. It is important we all minimise our social contact as much as we can this Christmas. That will help protect ourselves, our loved ones and the whole country.
"We know that the three-tiered system worked to control the old variant and is still working in large parts of the country, especially North of England.
"We also know it is not enough to control the new variant. It is not a hypothesis, it is a fact and we have seen it on the ground."
Other rule changes mean gyms and leisure centres will close, households will not be allowed to meet outdoors and people will largely be required to stay at home.
It also means an end to the rule of six, meaning with the exception of people from their single households, only two people can meet outdoors at one time.
The health secretary added that the new variant of the virus was spreading "at a dangerous rate".
He said: "I know these actions have consequences and I know how difficult it is. But I also know we have to take the action necessary to control this virus.
"Amid all this difficulty, the great hope for 2021 is, of course, the vaccine.
"The vaccine is our route out of all this and however tough this Christmas and this winter is going to be, we know that the transforming force of science is helping to find a way through.
"I'm delighted to be able to tell you that the Oxford AstraZeneca vaccine developed here in the UK has submitted its full data package to the MHRA for approval.
"This is the next step towards a decision on the deployment of the vaccine which is already being manufactured, including here in the UK."
Andrew Proctor, leader of Norfolk County Council, said: "With our hospitals under increasing pressure and the rates of the virus in the county continuing to rise over a number of indicators, the tougher restrictions for Norfolk isn't what we wanted to hear but in those circumstances doesn't come as much of a surprise.
"I know this isn't the news people want to hear at any time and particularly in the run-up to Christmas, but this new variant of the virus means that it is more important than ever that we work together to protect our loved ones, protect the NHS and protect Norfolk."
Mr Proctor also urged people to carefully consider their Christmas plans, adding: "We’d like to see family and friends on Christmas Day within the guidelines, but with cases in our county rising rapidly we have to ask ourselves ‘is it necessary?’, ‘can the time together be shorter?’ and ‘can our gathering be smaller?’ as well as: ‘is it safe?’ and ‘is it sensible?’"
He said: ‘It’s welcome news that decision has been made no matter how unpleasant going into tier four will be. If there is any doubt about what the restrictions are the default must be ‘just don’t do it’.
"Norfolk has shown we can stick together. Now we have to show it again. Digger even deeper is not easy, but every step we take together is one closer to coming out the other side of this before the summer."
It comes against a backdrop of record-high rates for the county, with Norwich the worst-hit area with an infection rate of 249 cases per 100,000 people for the week ending December 18.
Simon Bailey, chief constable of Norfolk police, said: "Reports of increasing infection rates associated with a new variant of Covid-19 will naturally cause concern among our communities.
"While traditionally this time of year lends itself to time with family and friends, the greatest gift we can give to our loved ones is respect and adherence to the regulations. I would encourage everyone to work together - we must follow the rules as it’s the only way to help stop the spread of the virus and reduce infections.”
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