LONDON (Reuters) - British Prime Minister Boris Johnson ordered millions more people to live under the strictest COVID-19 restrictions from Thursday to counter a new variant of the virus that is spreading at a “sheer pace” across the country. Case numbers have risen sharply in Britain in the last two weeks, driven in part by a new strain that is up to 70% more transmissible than the original. The government, which reported another 981 deaths from the virus in the last 24 hours, said three quarters of England’s population would be in the top tier of restrictions from 0001 on Thursday, covering 44.1 million people. In those areas, hospitality venues and non-essential shops are closed and households cannot mix. “We must face the reality that the sheer pace of the spread of this new variant requires us now to take even tougher action in some areas,” Johnson told a news conference. He urged people to stay at home on Thursday night and avoid any public New Year’s Eve celebrations. The government also said secondary schools would delay and stagger their reopening after Christmas to enable testing to be implemented, while some primary schools in the worst-hit areas will not open to all pupils. Britain has suffered one of the highest death tolls in Europe and the deepest economic contraction from the pandemic, spending much of 2020 in varying levels of lockdown to prevent its hospitals from being overwhelmed. In Scotland, large areas are under tough lockdowns where pubs, restaurants and cafes must close, while schools will open later than expected. Northern Ireland and Wales have their own similar, tough restrictions. Britain’s Health Secretary Matt Hancock said the country’s hospitals were coming under very significant pressure, with the number of people battling the virus on wards or intensive care as high as it was during the first wave. “Unfortunately, this new variant is now spreading across most of England and cases are doubling fast,” he told parliament. “It is therefore necessary to apply Tier 4 to a wider area.” London and surrounding areas were put into the newly created Tier 4 on Dec. 19. The Midlands, the north east, parts of the north west and parts of the south west will join them on Thursday.