LONDON — Prime Minister Boris Johnson of Britain has all the time taken a seat-of-the-pants strategy to governing. However his reversals this week on the two most urgent points going through the nation — the pandemic and Brexit — have been breathtaking, even by Mr. Johnson’s brashly improvisational requirements.

On Wednesday, alarmed by a resurgence of the coronavirus, Mr. Johnson introduced that the British authorities would ban gatherings of more than six people, after weeks of encouraging folks to return to work, eat out at eating places, patronize pubs and ship their kids again to high school.

Hours earlier, the authorities launched laws on Northern Eire that will override a landmark Brexit settlement that Mr. Johnson himself struck with the European Union, shepherded via Parliament and championed throughout final yr’s election on his option to a landslide victory.

The federal government admitted that this surprising transfer breaks worldwide legislation, which critics say raises a sticky query: Why ought to folks obey Mr. Johnson’s new guidelines on social distancing when he openly flouts a authorized treaty?

“It’s a madman, no-holds-barred fashion of governing,” stated Mujtaba Rahman, an professional on Brexit at the political danger consultancy, Eurasia Group. “You place your foot on the accelerator as onerous as you possibly can and hurtle your self in the direction of the cliff.”

Whether or not Mr. Johnson’s brinkmanship with the European Union will crash the present commerce negotiations or allow him to strike a greater deal was not but clear. European officers demanded urgent talks with Britain about its menace to rewrite the components of the Withdrawal Settlement that cope with Northern Eire. However they didn’t break off one other set of talks in London for a commerce deal.

Both means, Mr. Johnson’s strikes confirmed a readiness — one which dates again to his days as the mayor of London — to shift course instantly, contradict himself and thumb his nostril at conventional norms in pursuit of his objectives. And, as so usually in the previous, his strategies drive many in Britain’s institution to distraction.

One of his Conservative predecessors, John Main, stated of the Brexit reversal, “If we lose our popularity for honoring the guarantees we make, we can have misplaced one thing past value that may by no means be regained.”

Mr. Johnson’s about-face on lockdown guidelines was a clearer case of bowing to proof that the virus is spreading. After a tranquil stretch in June and July, new instances started to creep up in August. By final Sunday, that they had spiked to almost 3,000, the highest every day quantity since Could 23.

Well being officers stated they apprehensive that many of the instances had been in younger folks, elevating the hazard that Britain is on the identical path as France and Spain, the place a bounce in instances prompted Britain to impose a journey quarantine on each international locations.

The nation’s an infection fee has risen from 12.5 per 100,000 folks final week to 19.7 per 100,000, indicating that the “R quantity” — a measurement that reveals how many individuals are being contaminated on common by every particular person with the virus — has risen above one, a vital threshold.

“It’s a sew in time to save lots of 9,” Mr. Johnson stated at a information convention, flanked by his chief medical and scientific advisers. “These measures usually are not one other nationwide lockdown. The entire level of them is to keep away from a brand new nationwide lockdown.”

Well being specialists praised Mr. Johnson for imposing modest restrictions now, reasonably than risking a bigger spike, which might necessitate extra draconian measures. However they stated Britain’s insurance policies continued to be inconsistent. Authorities allowed a crowd to assemble for the opening day of horse races on Wednesday in Doncaster, in northern England, earlier than abruptly closing the relaxation of the races to spectators.

“The U.Okay. authorities is muddled and must resolve on a transparent technique as a result of in the present strategy, each the well being and the financial system will undergo, and compliance by the public will proceed to fall,” stated Devi Sridhar, professor and chairwoman of world public well being at the College of Edinburgh.

The blended messages replicate a lingering pressure inside Mr. Johnson’s cupboard and occasion between those that fear a couple of lethal second wave of infections this fall and winter and those that argue that extra lockdowns will throttle the financial system. Even now, Mr. Johnson insisted that colleges would keep open and that folks ought to nonetheless contemplate returning to work, so long as it was secure.

Critics additionally fault the authorities for failing after months to arrange an environment friendly nationwide test-and-trace program. The Labour Get together chief, Keir Starmer, confronted Mr. Johnson in Parliament on Wednesday with tales of individuals who had been informed they must journey lots of of miles to get a take a look at.

The federal government stated the police would levy fines of 100 kilos, about $130, on individuals who violated the six-person restrict. However Mr. Johnson deflected questions on whether or not he meant to “cancel Christmas,” a phrase that implies the tough choices the authorities will face on the virus as the fall and winter set in.

For Mr. Johnson, analysts stated, choosing a battle with the European Union was so much simpler. Tim Bale, professor of politics at Queen Mary, College of London, stated that in escalating the language on Brexit, Mr. Johnson had reverted to a examined technique that performed to the hard-core Brexit base in the Conservative Get together.

Whereas Mr. Johnson’s menace to renege on a treaty has outraged commentators and institution figures like Mr. Main and former Prime Minister Theresa Could, the authorities appears to have calculated it is going to trigger little blowback past political circles in Westminster.

“They appear to treat breaking worldwide legislation as a Beltway challenge reasonably than one thing that may trouble most individuals — and in that, they’re nearly actually proper,” Professor Bale stated, referring to the parochial politics of Washington.

Nonetheless, antagonizing the European Union 4 months earlier than the deadline for a commerce settlement is just not with out dangers. Mr. Rahman stated he now believes there’s a larger than even probability that Mr. Johnson will fail to strike a cope with Brussels, ushering in a interval of disruption on prime of the pandemic.

Having promised in the election to “get Brexit performed,” analysts stated, Mr. Johnson can also be taking a danger in prolonging the wrangling, as many Britons are merely sick of listening to about it. In January, if the fears of scientists are true, he might discover himself coping with a much more critical well being disaster.

“Covid is a a lot larger problem and the political dangers of being seen as incompetent are a lot larger,” Professor Bale stated. “Most voters are way more apprehensive about Covid, which impacts on them immediately, than the technicalities of authorized interpretations.”