“When the science changes, we must change our response. When the virus changes its methods of attack we must change our method of defence and as your Prime Minister I sincerely believe there is no alternative open to me,” he said.
Scotland and Wales, which have their own devolved governments, have also tightened their lockdown rules.
Welsh First Minister Mark Drakeford, of the Labour Party, has announced the entire country will go into lockdown from midnight, with Christmas easing reduced to a single day, as in non-tier four areas of England.
Scottish First Minister Nicola Sturgeon, of the left-separatist Scottish National Party (SNP), has closed Scotland’s borders with the rest of the United Kingdom, moved the entire mainland into the second-highest level of restrictions, and also reduced Christmas easing to a single day.
“I know how harsh it is, but this virus doesn’t care about anything apart from spreading as far and wide as possible,” she said, claiming that the new rules “make me want to cry”.
Northern Ireland is the only one of the British Home Nations which has not changed its Christmas plans — although this may change as the situation develops.
WATCH LIVE: An update on coronavirus (19 December 2020) https://t.co/zqVXIkifSd
— Boris Johnson (@BorisJohnson) December 19, 2020