Declaring that Britain would not return to the “broken model” of the past, Prime Minister Boris Johnson vowed Wednesday to engineer a radical transformation of the country’s economy to a future defined by highly skilled workers earning higher wages.

Projecting sunny optimism but offering few details, Johnson sketched a vision of Britain on the cusp of change. He barely mentioned the spate of fuel and food shortages that have afflicted the country in recent weeks, characterizing them as mainly the consequence of a rapidly recovering economy in transition.

In a speech to a cheering crowd at his Conservative Party’s annual conference, Johnson said, “We are going to deal with the underlying issues of our economy and society — the problems that no government has had the guts to tackle, the long-term structural weaknesses in the U.K. economy.”

It was, Johnson said, “a change of direction that has been long overdue,” adding, “We are not going back to the same old broken model: low wages, low growth, low skills and low productivity — all of it enabled, as a system, by uncontrolled immigration.”

The prime minister devoted much of the speech to his flagship policy of “leveling up,” which aims to even out disparities between the economically disadvantaged northern parts of England and its more prosperous South. As he put it, “We have one of the most imbalanced societies and lopsided economies of all the richer countries.”

But Johnson offered little in the way of concrete policies, apart from a bonus payment to math and science teachers in economically struggling areas. His other pledges — to improve housing, tackle crime and upgrade transportation networks in northern cities — struck a familiar note.

Johnson has branded his agenda “Build Back Better,” the same slogan President Joe Biden uses for his infrastructure legislation (both adopted it around the same time last year). Unlike Biden, the prime minister riffed on the line, adapting it to describe the return of beavers to British rivers (“Build Back Beaver”) and beef exports to the United States (“Build Back Burger”).

Mixing self-deprecating humor with historical and literary references, gleeful jabs at the opposition and a populist appeal to social issues, Johnson reinforced his status as the Conservative Party’s all-purpose cheerleader.

At one point, the prime minister, who has six children with multiple partners, lamented Britain’s comparatively small population, despite, he said, his best efforts to add to it. At another, he described the leader of the Labour Party, Keir Starmer, as the skipper of a cruise ship that had been hijacked by Somali pirates.

Johnson also appealed to social and cultural issues that resonate with the Conservative rank and file. He vowed to defend Britain’s history and to oppose revisionist interpretations of Conservative heroes like Winston Churchill.

And Johnson invoked Margaret Thatcher, another of his Conservative predecessors, to defend tax increases imposed by the government to compensate for massive pandemic-related spending. Thatcher, he said, would not have ignored “this meteorite that has just crashed through the public finances.”

For all the references to Conservative icons, however, Johnson’s speech amounted to a remarkable repudiation of the traditional guiding principles and governance record of his party.

The Conservatives have long been the party of business, yet Johnson, in effect, put the onus on firms to break their addiction to a low-wage economy. The Tories have led the government since 2010, yet Johnson spoke of the last decade as if some other party had been in charge.

To political analysts, Johnson appeared to be launching something new for the post-pandemic, post-Brexit era: a party that combines the free-spending, interventionist impulses of social democrats with the anti-immigration instincts of the Brexiteers who agitated to leave the European Union in 2016. His party was committed to “radical and optimistic Conservatism,” he said.

Johnson’s rhetorical acrobatics showcased a politician who has managed, time and again, to defy political gravity. His 40-minute speech, in a hall packed with party faithful, contrasted with the more subdued, sometimes sparsely attended, appearances by his Cabinet ministers in previous days. It underscored the prime minister’s complete control over the Conservative Party.

Still, as Britain confronts painful adjustments, Johnson faces a convergence of hostile trends that could test this high-wire act. Rising food and fuel prices are straining consumers; gas shortages have forced motorists to wait for hours to fill up their tanks.

Johnson has portrayed these challenges as growing pains — evidence of an economy awakening from the pandemic and remaking itself to reap the benefits of a high-wage, highly skilled future.

For ordinary people, however, the specter of fuel and food shortages as the autumn closes in harks instead to the 1970s and the period of strikes and soaring prices that newspapers called the “winter of discontent.”

Even some members of his own party seemed unconvinced, with one influential Conservative lawmaker, Tom Tugendhat, writing on Twitter that “rising wages are great unless prices rise faster. Inflation matters — it’s about what we can afford and how families make ends meet in a tough month.”

Critics also disputed Johnson’s claim that Brexit had allowed Britain to strike a new submarine alliance with the United States and Australia. Britain has long enjoyed an intelligence relationship with these nations, and national governments control defense within the EU.

Johnson tried to draw a new dividing line with the opposition Labour Party, which he painted as welcoming uncontrolled immigration — and the resulting low wages — while the Conservatives seek training and better pay for British workers.

Asked in an interview this week how Britain would deal with the immediate consequences of an economic transition that could take years, he echoed a phrase made famous by Thatcher: “There is no alternative.”

But Johnson’s comments dramatized the extent of his breach with her legacy. The party’s traditional relationship with business was strained over Brexit, which was opposed by major companies that took advantage of Europe’s massive single market. And in recent days, the prime minister has added to the tensions, chiding some businesses for what he said was a failure to invest in their workers.

While even his critics welcome the idea of moving away from a low-wage, low-skills economy, there could be pain ahead for Britons if the government’s policies cause inflation to spike and interest rates to rise. Much of the fiscal stimulus the government injected into the economy to cushion the pandemic’s blow — including paying most of the wages of people who had been sent home — has been wound down.

Johnson urged people to return to their offices but otherwise ignored cost-of-living issues. Instead he celebrated what he described as the unquenchable spirit of Britons. It was evident, he said, in the scientists who developed the AstraZeneca vaccine, the nurses of the National Health Service, and Emma Raducanu, the 18-year-old who won the U.S. Open tennis championship last month.

While those lines drew applause among Tories in the hall, the reaction from businesses across the country was far warier.

“Firms are dealing with a cumulative crisis in business conditions as supply chains crumple, prices soar, taxes rise and labor shortages hit new heights,” said the director-general of the British Chambers of Commerce, Shevaun Haviland, adding that “the economic recovery is on shaky ground.”