UK's chief scientific adviser Sir Patrick Vallance has said that there will be "inevitable" increases in Covid cases over the next few weeks in the country, as people mix more over Christmas.
He made the comment during a briefing of UK Prime Minister Boris Johnson at the Downing Street, BBC reports.
Sir Patrick Vallance said, "Work has been done to look at the new coronavirus variant. The view that it's transmitting more readily has been "reinforced", meaning the tiering system is vital."
Pippa Crerar of the Mirror asks why the whole country isn't in lockdown. She also asks why the PM keeps "overdelivering and under promising".
Sir Patrick Vallance said it was the case that the virus will spread more and adds that "measures are going to need to be increased in due course not reduced".
Boris Johnson said keeping the country in perpetual lockdown would have been disastrous.
"We can look forward to a very different world from Easter onwards," he added.
The UK PM promised to keep working for new treatments and revealed that more than 500,000 people in the UK have had their first vaccine dose.
Boris Johnson further said that he and French President Macron hope to unblock the flow of trade "in the next few hours".
France has closed its border with the UK for 48 hours, with no lorries or ferry passengers able to sail from the port of Dover.
More than 40 countries have banned UK arrivals because of concerns over the spread of a new variant of coronavirus. Spain, India, Hong Kong, Canada, Switzerland and Germany are the latest to suspend UK flights.
A further 33,364 positive cases have been recorded in the UK, as well as a further 215 deaths within 28 days of a positive test.