Boris Johnson has said new measures could be introduced to stop the spread of the Omicron strain of Covid-19.

The Prime Minister today (December 20) led a special two-hour meeting of the Cabinet and said they were monitoring the data “hour by hour”.

Johnson added that the arguments for taking action were “very, very finely balanced” – indicating fresh measures were unlikely before Christmas Day.

“Unfortunately I must say to people that we will have to reserve the possibility of taking further action to protect the public, to protect public health, to protect our NHS,” he said.

“We are looking at all kinds of things to keep Omicron under control and we will rule nothing out.

“But at the moment, what I think we want people to focus on is exercising caution – so ventilation, masks in the appropriate places, all the usual stuff about washing hands, but remember how contagious Omicron is.”

Ministers were briefed at the virtual meeting on the latest situation by the Government’s chief scientific adviser Sir Patrick Vallance and England’s chief medical officer Professor Chris Whitty.

It comes after the Government’s Scientific Advisory Group for Emergencies (Sage) warned daily hospital admissions could reach 3,000 without further restrictions.

However, Mr Johnson said there were still “uncertainties” around the severity of the new strain, as well as the rate of hospital admissions associated with it, and its impact on the effectiveness of the vaccines.

At the same time, he said they needed to take account of the economic impact of any new measures – particularly on those sectors which were already struggling due to the pandemic.

“There are still some things that we need to be clearer about before we decide to go further,” he said.

“[We must act] cautiously but it is also important we look after the hospitality industry, the theatres and other parts of our incredible entertainment industry which have suffered and are suffering.”

There was relief among some Conservative MPs who rebelled last week over the Government’s plans for Covid passports that ministers had stopped short of imposing controls in the final days before Christmas.

Former cabinet minister Esther McVey tweeted: “Pleased the Cabinet and PM (recognising where majority opinion is in parliamentary party) are now listening to their backbench MPs and for once pushed back on the scaremongering by the lockdown fanatics.

“It seems the 100 strong backbench rebellion last week has made a difference.”

However, Labour, which has said it would support the Government over any further public health measures that were needed, accused the Prime Minister of putting party interests before the country.

Shadow health secretary Wes Streeting said: “Boris Johnson is too weak to stand up to his backbenchers, many of whom have no plan beyond ‘let the virus rip’.

“Today, while businesses across the country wonder if they can continue to trade, and families make frantic calls about whether they will see each other this Christmas, true to form the Prime Minister has put his party before the public.

“Rather than set out a clear plan for the country, he has chosen to protect himself from his MPs by simply not saying anything. Boris Johnson is unfit to lead.”