British Prime Minister Boris Johnson has set out the government's response to the new COVID-19 Omicron variant at a Downing Street press conference.
Flanked by Professor Chris Whitty and Sir Patrick Vallance, his chief medical and scientific advisers, Johnson said the UK's plan "has been working", with falling numbers of hospitalisations and deaths.
"It does appear that Omicron spreads rapidly, and can be spread between people who are double vaccinated", Johnson said, and "could reduce the protection of our vaccines over time".
"We need to slow down the seeding of this variant" to "buy scientists time" and help the NHS prepare, he said. Intensive testing will be introduced in areas where outbreaks occur.
Anyone entering the UK will have to take a PCR test within 48 hours, and self-isolate until they test negative. Anyone coming into contact with a person infected with the new variant will have to isolate for 10 days, regardless of their vaccination status.
Johnson also said the government would "tighten up" rules for wearing face coverings in shops and on public transport. But he insisted that all new measures would be "temporary" and reviewed in three weeks' time.
Pressed on whether public mask-wearing would be made mandatory again, he said Health Secretary Sajid Javid would announce the details in the coming days.
But a tweet on the official 10 Downing Street account said masks would now be "compulsory" in shops and on public transport, but not in "hospitality" settings — pubs, restaurants, and hotels.
And the PM said the COVID vaccine booster dose programme would be sped up with the target of six million more jabs in the next few weeks, taking the total to around 23 million.
"The best thing you can do is get your booster", Johnson stressed.
Whitty and Vallance repeated fears of the World Health Organisation and others that the new variant may be more transmissible and could possibly bypass immunity from existing vaccines and infections due to the large number of mutations identified in its surface proteins.