LONDON — With coronavirus circumstances in Britain exploding, driven by the extremely transmissible Omicron variant, the govt is leaving open up the chance of soon imposing one more spherical of restrictions, the country’s health secretary explained on Sunday.

Scientific advisers have warned lawmakers that a lot more motion is needed, since the surge is threatening to overwhelm the country’s health procedure, even immediately after the govt introduced a extensive-resisted coronavirus contingency plan previously this month, urging persons to do the job from residence if attainable and extending a experience-mask mandate.

More than the weekend, Sadiq Khan, London’s mayor, declared a “major incident” — an unexpected emergency position that frees up assets — in the capital, and speculation on the chance of a shorter-time period nationwide lockdown has been swirling.

The fears of a community health and fitness crisis only days right before Christmas have coincided with a political crisis for Primary Minister Boris Johnson, deepened by the resignation on Saturday of David Frost, the Brexit negotiator and a essential ally, who cited his opposition to lockdown measures when he give up. On Sunday, Downing Street announced that the international secretary, Liz Truss, would consider more than Brexit responsibilities.

The timing of Mr. Frost’s resignation underscores the acute political perils confronting Mr. Johnson as he considers imposing restrictions on Britons for the next Xmas in a row, irrespective of fierce opposition from Mr. Frost and several many others in his Conservative Occasion who have objected to the actions on the grounds that they could jeopardize the financial system and restrict independence.

Though the government has refrained from saying a lockdown, the wellness secretary, Sajid Javid, seemed to be priming the public on the probability when he refused on Sunday to rule out the possible for much more stringent steps just before Saturday.

“There are no guarantees in this pandemic,” he reported. “At this issue, we just have to keep anything below critique.”

Mr. Javid did not deny speculation that the governing administration was thinking about a two-week “circuit breaker” that could mean curbs on pubs and dining establishments, and the government’s emergency committee held a…