LONDON (Reuters) - Scotland on Monday imposed the most stringent COVID-19 lockdown since last March and British Prime Minister Boris Johnson said he would shortly impose tougher curbs in England to contain a rapidly spreading outbreak of a new variant of the coronavirus. The United Kingdom has the world’s sixth-highest official coronavirus death toll - 75,024 - and the number of new infections is soaring across the country. As Johnson mulled tougher measures for England, Scottish First Minister Nicola Sturgeon said the new variant accounted for nearly half of new cases in Scotland and is 70% more transmissible. Scots, she said, would be legally required to stay at home for January from midnight. Schools will close for all but the children of essential workers. “I am more concerned about the situation that we face now than I have been at any time since March,” Sturgeon told the Scottish parliament. “As a result of this new variant, (the virus) has just learned to run much faster, and has most definitely picked up pace in the past couple of weeks,” Sturgeon said. Visiting a hospital to see the first people receive the vaccine made by Oxford University and AstraZeneca, Johnson said the country faced “tough, tough” weeks to come. “If you look at the numbers, there’s no question that we’re going to have to take tougher measures and we’ll be announcing those in due course,” Johnson said. “We’ve got the virus really surging.” England, Scotland, Wales and Northern Ireland implement their own COVID-19 responses though they are trying to coordinate more across the United Kingdom. FILE PHOTO: Scotland"s First Minister Nicola Sturgeon visits Western General Hospital amid the spread of the coronavirus disease (COVID-19) in Edinburgh, Scotland, Britain, December 7, 2020. REUTERS/Russell Cheyne/Pool/File Photo SCHOOLS England is currently divided into four tiers of restrictions, depending on the prevalence of the virus, with the vast majority of the country in Tiers 3 and 4 where social mixing is restricted and restaurants and pubs are closed. Health Secretary Matt Hancock said earlier that the rules in Tier 3 were clearly not working. With England moving back towards the strict lockdown of the first wave in March, Johnson was also asked if schools would have to close once again and return to online learning. He said that would remain a last resort for primary schools given the social and educational damage that can be done to isolated children. But he indicated they may need to rethink a plan to reopen secondary schools for pupils aged between 11 and 18. “It looks as though secondary schools probably play more of a role in the spread of the epidemic than primary schools, so we’ll have to look very hard at what we do with secondary schools later in the month,” he said. The government has spent the year trying to balance the need to shut down the country to contain the virus without hammering the economy. The first national coronavirus lockdown in May last year prompted a 25% drop in economic output - unprecedented in modern records - leaving Britain’s economy harder hit by the pandemic than most others. While the economy recovered partially in the third quarter, renewed lockdown measures threaten to cause a double-dip recession at the start of 2021.