British Prime Minister Boris Johnson outlined new coronavirus measures at a press conference on Wednesday.
The announcements come amid fears over new COVID-19 variant Omicron, whose doubling time in the UK is estimated "between two and three days," said Johnson.
"It has become increasingly clear that Omicron is growing much faster than the previous delta variant and is spreading rapidly all around the world," he told reporters
Johnson said 568 cases of the Omicron variant have been confirmed so far across the UK, and "the true number is certain to be much higher."
Johnson said England would "move to plan B" and reintroduce guidance to work from home from Monday as well as a requirement to wear facemasks, including indoors.
From next week, having a COVID-19 pass showing a person has had both vaccine doses will be mandatory to enter nightclubs and places with large crowds, the prime minister said.
Live music venues and nightclubs, which have long resisted vaccine passports, called the news devastating for an industry that's just finding its feet again after prolonged periods of closure and restrictions. The blow is particularly hard ahead of the crucial Christmas and New Year period, they said.
The new measures come as the government faces sharp criticism after a leaked video showed senior members of Johnson's staff joking about holding a lockdown-breaching Christmas party.
The video has poured fuel on allegations that government officials flouted coronavirus rules they imposed on everyone else.
Several questions at the press conference focused on the allegations. "We've followed the rules throughout, on Dec 18 as well," Johnson insisted.
He has ordered an inquiry into the allegations earlier on Wednesday.