LONDON — The British government has extended its highest tier of restrictions to three-quarters of England's population, saying a fast-spreading variant of the coronavirus has reached most of the country.

Health Secretary Matt Hancock says the top Tier 4 would be extended beyond London and the southeast to large swaths of central, northern and southwest England.

Under the measures, people are advised to stay home, household mixing is banned, nonessential shops are closed and restaurants and bars can only offer takeout.

Hancock says the authorization of a new 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."