LONDON (AP) — The British government on Wednesday extended its toughest coronavirus restrictions to more than three-quarters of England’s population, saying a fast-spreading new variant of the virus has reached most of the country.

Health Secretary Matt Hancock said that at midnight the government's top infection-warning level, Tier 4, would be expanded beyond London and the southeast to cover large swaths of central, northern and southwest England, including the major cities of Manchester and Birmingham.

The move will severely curtail New Year's Eve celebrations in parts of England that are home to 44 million people, or 78% of the population. Prime Minister Boris Johnson said the government “intensively” considered imposing a nationwide lockdown but had decided against one for now.

In England's Tier 4, most people are advised to stay home, barred from mixing with the members of other households either indoors or out, nonessential shops are shut and restaurants and bars can only offer takeout.

Scotland, Wales and Northern Ireland also have implemented strong lockdown measures.

Hospitals in the worst-hit areas of London and southern England are becoming increasingly overstretched, with ambulances unable to unload patients at some hospitals where all the beds are occupied. There are more people in hospitals with COVID-19 now than at the first peak of the outbreak in April.

Britain has recorded more than 72,500 confirmed coronavirus deaths, the second-highest death toll in Europe after Italy and the sixth-highest worldwide. The country reported a record number of new confirmed cases on Tuesday, more than 53,000, and 50,023 on Wednesday.

The U.K. also reported Wednesday that another 981 people with the coronavirus had died. It was the highest daily number of deaths reported since April, although it followed a lag in reporting over the Christmas holidays.

Hancock said Wednesday’s authorization of a second vaccine for use in the U.K. was good news, but “sharply rising cases and the hospitalizations that follow demonstrate the need to act where the virus is spreading.”

He told lawmakers in the House of Commons that the medicines regulator's approval of the vaccine made by British pharmaceutical company AstraZeneca and Oxford University "brings forward the day on which we can lift the restrictions,”

“But…we must act to suppress the virus now, especially as the new variant makes the time between now and then even more difficult.”

In addition to the wider restrictions, the government delayed the return to school after the Christmas break for millions of students. Education Secretary Gavin Williamson said secondary schools in England would not resume in-person teaching until Jan. 11.

Most primary schools will welcome students back on Monday as planned, although not the ones in some virus hotspots, including a big chunk of London.

Johnson said the Oxford-AstraZeneca vaccine and another already in use developed by U.S. drugmaker Pfizer and Germany company BioNTech meant “there are plenty of reasons for people to be optimistic about the spring.”

However, Johnson said, “people should not in any way think that this is over.”