LONDON — When Prime Minister Boris Johnson of Britain convened his new cabinet on Friday, it looked less like a conclave of powerful government officials than a well-mannered classroom on the day the headmaster came to visit.
“How many hospitals are we going to build?” Mr. Johnson asked.
“Forty,” they replied in unison.
“How many more police officers are we recruiting?” he demanded.
“Twenty-thousand,” they chanted.
Such a display of lock step discipline is a striking change in a country that became used to clamorous politics under Mr. Johnson’s predecessors, David Cameron and Theresa May, who struggled to hold together balky coalitions and govern without a Parliamentary majority.
In the two months since Mr. Johnson won a landslide election victory and rolled up an 80-seat majority, he has moved rapidly to take control of the levers of power. And to a degree unmatched by any British leader since Tony Blair, the government is now almost entirely subordinate to him.
But what Mr. Johnson intends to do with all this power is still not totally clear — though the decisions he has made over the last few weeks suggest he would prefer to govern as a more centrist, less radical figure, than the politician who waged a populist campaign on the promise that he would “get Brexit done.”
In amassing his power, Mr. Johnson has displayed what is to some a surprising degree of ruthlessness. Even Mr. Blair did not dare move against his finance chief as Mr. Johnson did this week, when he triggered the departure of Sajid Javid, the chancellor of the Exchequer.
Mr. Javid, an ally of Mr. Johnson’s, resigned rather than have many of his powers stripped and handed over to Mr. Johnson’s aides in 10 Downing Street.
The chancellor is considered Britain’s second-most powerful official after the prime minister; several have emerged as rivals to the leader. In appointing Rishi Sunak, a 39-year-old former investment banker who won his seat in Parliament only in 2015, Mr. Johnson is out to make sure that the Treasury will not curb his free-spending agenda.
“A lot of prime ministers would worry about losing their chancellor of the Exchequer, but he realized he and Javid didn’t see eye to eye on economic policy,” said Andrew Gimson, who wrote a biography of Mr. Johnson.
“He won a decisive victory and he is using the freedom that comes from such a majority to put in the people he wants,” Mr. Gimson said. “At the moment, he completely dominates British politics.”
Last week, in his first major decision, Mr. Johnson approved a gargantuan high-speed rail project that is designed to link London with the country’s economically challenged north. Some of his own aides and members of the Conservative Party fiercely opposed the project, known as High Speed 2, because of the $130 billion-plus price tag.
But for Mr. Johnson, ambitious public-works projects symbolize his pledge to pour resources into Britain’s Midlands and north, where many lifelong Labour Party voters defected to the Conservatives in the election, helping the prime minister pile up his Parliamentary majority.
“Everything this government has done bears the mark of careful consideration and triangulation,” said Anand Menon, a professor of European politics at King’s College London. “They’ve created a narrative that the government is radical while the government does not do anything radical.”
Jonathan Powell, a former chief of staff to Mr. Blair, said mandates of the kind enjoyed by his old boss and Mr. Johnson were fleeting. He said Mr. Johnson risked making the same mistake Mr. Blair did in not moving quickly enough.
“I’m surprised by how little he is doing with it,” Mr. Powell said. “Perhaps he wants to be the nonexecutive chairman of the government.”
Mr. Johnson is also still busy appealing to his pro-Brexit base with populist tactics like attacking the BBC, Britain’s public broadcaster. He has accused the BBC of biased reporting and threatened it with legal changes that could dry up its sources of funding.
The prime minister’s clash with Mr. Javid was a victory for his influential adviser, Dominic Cummings, who has made a crusade of overhauling the government and centralizing power in the prime minister’s office.
But Mr. Javid’s departure may be more important because of what it says about Mr. Johnson’s fiscal policies. The Treasury, under Mr. Sunak, is expected to loosen limits on government spending, which would allow Mr. Johnson to pursue a liberal economic agenda not unlike that of a Social Democrat in continental Europe.
In that sense, he is starkly different from President Trump, another populist politician to whom he is regularly compared — and who is also known for running extremely compliant cabinet meetings.
During his 2016 presidential campaign, Mr. Trump spoke privately about his intention to govern as a pragmatist and champion of the working class. Yet after he was elected, he enacted some of the most radical parts of his agenda, like clamping a travel ban on majority-Muslim countries, and rammed through a tax cut favoring corporations and the wealthy.
Mr. Johnson, some commentators argue, is less like Mr. Trump than Michael R. Bloomberg, the onetime Republican who was mayor of New York and is now running for the Democratic presidential nomination. Like Mr. Bloomberg, Mr. Johnson was a big-city mayor, in London. And like Mr. Bloomberg, he likes to apply the lessons of running a municipality to the national stage.
“It makes a lot of sense of his premiership if one thinks of him as trying to be mayor of the U.K.,” wrote Daniel Finkelstein, a columnist for The Times of London. “Mayors tend to be pragmatists who know they are judged by whether they get the pavement clear of snow rather than by the speeches they make.”
Whether Mr. Johnson’s policies will succeed in clearing Britain’s streets is another question. After Mr. Javid’s departure, the government could not say that its budget will be rolled out as planned on March 11. Nor could it confirm that it will adhere to strict constraints on borrowing, even though these were mandated in the Conservative Party’s election-winning manifesto.
On Friday, the cabinet discussed plans for a post-Brexit immigration system, underscoring another of the complex challenges Mr. Johnson faces. His aides say the new system would give priority to those with qualifications, with a goal of attracting the brightest immigrants and reducing the numbers of those arriving will few or no skills.
That would appeal to Mr. Johnson’s base, given the role that anti-immigration fervor played in the 2016 Brexit referendum campaign. But in the short term, such a system could crimp economic growth as employers struggle to recruit at a time when Britain is close to full employment.
“There is a danger that we have promised something we can’t deliver,” said Jagjit Chadha, director of the National Institute of Economic and Social Research, a research institute based in London.
As Mr. Johnson consolidated his grip on government, his aides were busy trying to douse questions over who paid for an expensive holiday vacation for the prime minister on the chic Caribbean island of Mustique.
In a public filing, Mr. Johnson said the £15,000 cost of the vacation — almost $20,000 — was picked up by David Ross, a British billionaire who co-founded Carphone Warehouse. But Mr. Ross said he only “facilitated” the rental of a villa for Mr. Johnson and his 31-year-old partner, Carrie Symons, leaving the question of who actually paid for it a mystery.
Labour lawmakers have called for an inquiry into the affair.
The timing could be problematic for Mr. Johnson. Mr. Powell, the former chief of staff to Mr. Blair, noted that in 1997, Mr. Blair’s new government was crippled by a fund-raising scandal involving the Formula One mogul, Bernie Ecclestone.
For those who have followed Mr. Johnson’s surprising career, it was a reminder that scandals always seem to trail him.
“The public, in this age of populist leaders, tolerates dishonesty,” Mr. Menon said. “The one thing the public doesn’t like is a sniff of corruption.”