Here's when lockdown could end in England - according to latest government advice
He ordered the country to stay indoors other than for limited exceptions and bowed to significant pressure to order primary schools, secondaries and colleges to move to remote teaching for the majority of students from Tuesday.
The Prime Minister warned: “the weeks ahead will be the hardest yet but I really do believe that we’re entering the last phase of the struggle, because with every jab that goes into our arms we’re tilting the odds against Covid and in favour of the British people.”
But how long could England be placed under strict lockdown restrictions?
When did the new lockdown period start in England?
The restrictions came into force at midnight on the morning of January 5.
How long will lockdown last?
England was placed under lockdown for an initial period of six weeks.
In a televised address to the nation the Conservative Party leader said that England would be under lockdown measures until at least mid-February.
Prefacing the confirmation of a lockdown, Mr Johnson said: "Our hospitals are under more pressure than ever before – England’s hospitalisations have increased by 30% in the last week.
"On the 29 December, more than 80,000 people tested positive for Covid across the UK - a new record. Deaths are up by 20% in the last week and will rise further.
"It’s clear we need to do more together."
Since then foreign secretary Dominic Raab has said that measures might not be eased until March and that restrictions will be “phased out” in specific parts of the country.
Vaccines minister Nadim Zahawi echoed Raab’s comments, stating that measures would need to be in place until “two to three weeks after the middle of February.”
Reflecting on the vaccine rollout timeline he said: "If we take the mid-February target, two weeks after that you get your protection, pretty much, for the Pfizer/BioNTech, three weeks for the Oxford/AstraZeneca, you are protected.
"One of the things we don't know yet, and the deputy chief medical officer Jonathan Van-Tam is on record as saying 'look give me a couple of months and I'll tell you', is the impact of the vaccine on transmission rates ie on infecting people.
"So there are a number of caveats that stand in the way of us reopening the economy.
"It will be gradually, it will be probably through the tiered system but you're looking at that sort of period, two to three weeks after the middle of February, after we've protected the top four cohorts."
When is the next lockdown review?
The UK government is bound by law to review measures every two weeks.
The next scheduled review of measures is on January 20.