Prime minister Boris Johnson has urged for caution as he opted against introducing any new immediate Covid restrictions.

However, Mr Johnson said the government 'would not hesitate to take action' and is monitoring the situation 'hour by hour'.

“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.

When asked about implementing new restrictions including in the hospitality sector, he told reporters: “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 really is."

Mr Johnson added that people have 'naturally' decided to go out less as Omicron spreads.

The prime minister said: “I understand how tough it must be and nobody wanted things to go this way.

“Omicron has simply exploded so fast that we have seen people naturally deciding to make sure that they protect themselves and they avoid spreading the disease.”

He added: “As I said, the benefits of that course of action we may see in the next few days and weeks in the way we are able to contain the disease.

“It is important we 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.”

Mr Johnson said the arguments for taking action in the face of the spread of Omicron were 'very, very finely balanced.'

“We have got cases of Omicron surging across the country now," he said.

"We have got hospital admissions rising quite steeply in London and the obvious conclusion is that it was right to go fast with Plan B in the way that we did and also right to double the speed of the booster rollout.

“In view of the balance of risks and uncertainties, particularly around the infection, hospitalisation rate of Omicron – how many people does Omicron put in hospital – and some other uncertainties to do with the severity, the effectiveness and so on we agreed that we should keep the data from now on under constant review.”