LONDON, Dec. 9 (Xinhua) -- A further 249 cases of the Omicron coronavirus variant have been reported in Britain, taking the total to 817, British health authorities said Thursday.

The latest daily figure came after 131 new cases of the Omicron variant were confirmed on Wednesday.

At a Downing Street press conference on Wednesday evening, British Prime Minister Boris Johnson said the variant’s doubling rate could be between two to three days, highlighting just how infectious the new strain is.

The rise in cases of the variant showed it is spreading even faster than Johnson had predicted.

Britain registered 50,867 new coronavirus infections, bringing the total number of cases in the country to 10,660,981, according to official figures released Thursday.

The country also reported a further 148 coronavirus-related deaths, taking the national death toll to 146,135.

Johnson has announced that Britain will move to "Plan B" restrictions to combat the rapid spread of the Omicron variant this winter.

The prime minister has asked people to work from home when possible from Monday while announcing that face masks would be a legal requirement in "most public indoor" areas such as theaters and cinemas from Friday.

Proof of two vaccine doses or a negative coronavirus test will be necessary for those wanting to enter nightclubs and large venues from next week, Johnson said, adding that people who are contacts of Omicron cases could face daily testing instead of undergoing a period of isolation.

More than 89 percent of people aged 12 and over in Britain have had their first vaccine dose, and over 81 percent have received both, according to the latest figures. Some 37 percent have received the booster jab, or the third vaccine dose.