Mr Johnson’s announcement came after days of speculation that England could introduce further Covid restrictions in the run-up to Christmas.

In a video statement, he said: “There is no doubt that omicron continues to surge with a speed unlike anything we’ve seen before. The situation remains extremely difficult, but I also recognise that people have been waiting to hear whether their Christmas plans are going to be affected.

“In view of the continuing uncertainty about several things – the severity of omicron, uncertainty about the hospitalisation rate or the impact of the vaccine rollout or the boosters, we don’t think today that there is enough evidence to justify any tougher measures before Christmas.

“We continue to monitor omicron very closely, and if the situation deteriorates we will be ready to take action if needed.

“What this means is that people can go ahead with their Christmas plans – but the situation remains finely balanced and I would urge everyone to exercise caution, to keep protecting yourselves and your loved ones, especially the vulnerable.

“And remember to keep following the guidance – wear a mask indoors when required to do so, keep fresh air circulating and take a test before you visit elderly or vulnerable relatives.”

Earlier, Mr Sunak warned that the UK faced an “enormous amount of uncertainty” which meant further restrictions before the New Year could not be ruled out. “We’re reviewing the data day by day, hour by hour, keeping the situation under constant review,” he said.

A source said Ms Truss wanted to see a proper economic impact assessment plus the relevant health data before she would support any extra restrictions. 

The source said she considered herself to be both in the libertarian camp with Jacob Rees-Mogg, the Commons Leader, and with economic sceptics led by Mr Sunak.