NHS England will return to highest level of emergency preparedness with the Omicron variant causing alarm among experts, it has been announced.
The move by health service bosses comes after the Prime Minister warned of a "tidal wave of Omicron", with cases of the mutant strain rocketing.
MPs were today told that the mutant strain will become dominant in London within 48 hours, while Boris Johnson confirmed at least one person had died after contracting Omicron in the UK.
In a televised address last night, the PM said it had become clear that two jabs of a Covid vaccine were "not enough" to provide protection against the variant.
And today Health Secretary Sajid Javid told MPs that there are now estimated to be 200,000 infections a day.
He said: "There are now 4,713 confirmed cases of Omicron in the UK.
"And the UK Health Security Agency estimates that the current rate of, the current number of daily infections are around 200,000.
"While Omicron represents over 20% of cases in England, we've already seen it rise to over 44% in London and we expect it to become the dominant Covid 19 variant in the capital in the next 48 hours."
The Health Secretary added: "In preparation, the UK's four chief medical officers raised the Covid alert level to four, its second highest level, this was done over the weekend.
"And NHS England has just announced that it will return to its highest level of emergency preparedness, level four national incident.
"This means the NHS response to Omicron will be coordinated as a national effort rather than led by individual trusts."
He told the House of Commons that the government's Plan B was being brought in to protect the public.
He said: "These are steps that no Health Secretary would wish to take unless they were absolutely necessary, but I am convinced that if we don't prioritise the booster now the health consequences will be far more grave in the months that lie ahead."
He added: "Because of the threat of Omicron we are moving to Plan B in England, subject to the will of this House."
He went on: "Even with Plan B, we still have far fewer restrictions in place than Europe. I can also confirm that from tomorrow fully vaccinated contacts of a Covid-19 case will now be able to take a daily lateral flow test instead of self-isolating."
Mr Johnson today refused three times to rule out introducing more restrictions before Christmas - as Scotland's Health Secretary said stricter rules are "inevitable".
Speaking during a visit to a vaccination clinic near Paddington, in west London, the Prime Minister said: "Omicron is producing hospitalisations and sadly at least one patient has been confirmed to have died with Omicron.
"So I think the idea that this is somehow a milder version of the virus, I think that's something we need to set on one side and just recognise the sheer pace at which it accelerates through the population.
"So the best thing we can do is all get our boosters."
