Downing Street insiders have said there is a 20% chance of Plan B restriction being enforced ahead of Christmas.

Prime Minister Boris Johnson has previously said the government plans for a rapid rise in Covid rates are unlikely to materialise in England.

A source told The Sun: "I reckon there’s a less than 20 per cent chance we’ll need to activate Plan B."

Speaking about the potential restrictions last week, Mr Johnson’s official spokesman said: The PM's official spokesman said: "There is absolutely no plan to introduce Plan B currently. We retain that capability if required if we believe the NHS is coming under unsustainable pressure.

"We obviously keep very close watch on the latest statistics. We always knew the coming months would be challenging."

What restrictions would return if Plan B is introduced?

Key restrictions to be reintroduced would be face masks, working from home and Covid vaccine passports.

The Plan B proposals draw on the findings of a review into vaccine passports earlier this year, which concluded that certification could help keep events going and businesses open.

Government plans set out how all visitors aged 18 and over to certain events could be required to be fully vaccinated.

The events listed are all nightclubs, and other venues open after 1am with alcohol, music, and dancing, and indoor events with 500 or more attendees where they are likely to stand and mix to a significant degree, or move around during the event, such as music venues or large receptions.

The plan also includes outdoor, crowded settings with 4,000 or more attendees where they are likely to stand, or move around during the event, such as festivals, and any settings with 10,000 or more people, such as large sports and music stadia.