Addressing the nation just after 6pm tonight ( Wednesday) Boris Johnson said that it is clear that Omicron is spreading faster than the Delta variant - and that the 568 cases of the variant in the UK is almost certainly underestimated.

The Omicron variant has emerged on the back of a high rate of Delta infections, Prof Chris Whitty, England's chief medical officer, added, with Johnson underlining Plan B will now come into force.

How Plan B will affect you:

Working from home:

Johnson says: "It's now the proportionate and the responsible thing to move to Plan B." From Monday people must work from home."

Covid pass mandatory for venues

Johnson said: "We will also make the NHS COVID pass mandatory for entry into nightclubs and venues where large crowds gather, including unseated indoor venues with more than 500 people, and seated outdoor venues with more than 4000 people and any venue with more than 10,000 people."

Mandatory face masks:

Johnson said:"From this Friday [December 10] we will further extend the legal requirement to wear a face masks in public indoor venues, including theatres and cinemas."

Johnson added that the government will be guided by four key factors including the efficacy of vaccines, the severity of Omicron, the speed of its spread and the rate of hospitalisations.

When asked why he is not introducing mandatory vaccines Johnson added: "I didn't want us to have a society in a culture where we forced people to get vaccinated."

However, Johnson said further measures could be considered.