Johnson says U.K. restrictions will probably get tougher

In an interview with the BBC's Andrew Marr on Sunday, Johnson didn't elaborate on what kind of additional measures might be needed and rejected criticism that his government has been too slow to act as the more contagious form of the virus spreads rapidly across the country.

"It may be that we need to do things in the next few weeks that are tougher in many parts of the country," Johnson said. "The U.K. is grappling with a new variant of the virus which is surging particularly in London and the southeast and that's why we've had to take exceptional measures for some parts."

One of the biggest questions now facing the government is how to manage school reopenings at a time when U.K. virus cases are surpassing 50,000 a day. Johnson's administration has been trying to keep in-person classes in England going throughout the pandemic, and on Sunday the prime minister sought to reassure parents that schools are safe and the virus poses little risk to young people.

"We've kept schools going for a long, long time in areas where the pandemic is in very high levels," Johnson said. "We've got to keep things under constant review, but we will be driven not by any political considerations, but entirely by the public health question."

Johnson's statements contrast sharply with warnings coming from teachers' unions, which have told members not to return to classrooms. In London, which has one of the country's highest levels of covid-19 infections per capita, the government has ordered all primary schools to remain closed for the start of the new term this week.

Keir Starmer, leader of the opposition Labour Party, went further, calling on the government to impose a national lockdown within 24 hours.

Throughout the pandemic, the U.K. government has been forced to backtrack several times on efforts to reopen the economy, especially as the virus's winter resurgence pushes public health services to the brink. Most recently, Johnson was forced to U-turn on plans that would have relaxed social-distancing rules over Christmas.

When asked about the U.K.'s plans for mass vaccinations, Johnson didn't offer any detail about how the country would be able to deliver 2 million vaccines a week.

"Everybody's working flat out to do this," he said. "We do hope that we will be able to do tens of millions in the course of the next three months."

In Scotland, First Minister Nicola Sturgeon asked for the parliament in Edinburgh to be recalled on Monday so she can lay out extra measures to curb rising infections. At the moment, schools are due to return for face-to-face teaching on Jan. 18 after a prolonged Christmas break.

Daily covid-19 cases have been rising to records and Sturgeon has said the country faces its most critical weeks since the pandemic began. The new strain counts for four in 10 new infections, a University of Edinburgh public health expert told the BBC.