One after the other, Britain’s recent prime ministers have pledged to revive the nation’s economy. One after the other, the promised growth eluded them.

Andy Burnham, set to formally become the newest prime minister on Monday after being named head of the Labour Party on Friday, has arrived with his own version of this pledge: “Good growth in every British postcode.”

His plan? Give away power to local officials so they can make their own economic choices. Mr. Burnham has promised to bring about “the biggest change in our lifetimes to the way the country is run.”

Mr. Burnham has not revealed the details of his economic agenda. But his priorities are emerging in his speeches and recommendations from advisers. The New York Times spoke with five economists and policy strategists who are playing a role in formulating Mr. Burnham’s economic vision, several of whom spoke on the condition of anonymity to talk openly about policies that were still not final.

Alongside the so-called devolution of power, Mr. Burnham has said he will bring more public utilities and services under public control, while quickly tackling the high cost of living.

But Mr. Burnham will face the same economic challenges that befell his predecessors: a heavy public debt burden, stubbornly high inflation and low productivity growth. Those are compounded by the unavoidable legacies of the country’s decision a decade ago to leave the European Union, which has dragged on the economy, and years of too little public investment. Nervous consumers are saving a lot, rather than spending.

Mr. Burnham faces formidable economic problems, but at their heart is stalled growth.

Britain’s economy has been sluggish since the 2008 financial crisis. Gross domestic product per person is just 7 percent higher than it was in early 2008, compared with more than 20 percent in the decade before the crisis.

“Growth is the big challenge the U.K. faces,” said David Aikman, the director of the National Institute for Economic and Social Research, an independent think tank. The country’s more enduring problems like how to fund the clean energy transition and support an aging population “would look a lot easier if we had faster growth,” he added.

Many of the big economic troubles, like high debt and huge demands on public spending, aren’t unique to Britain. But Mr. Burnham is bound by constraints of his — and his party’s — own making. Wary of spooking international buyers of British government debt and raising borrowing costs further, he has pledged to stick to strict rules on debt and spending made by Rachel Reeves, whom he is expected to replace as chancellor of the Exchequer in coming days. Mr. Burnham will also inherit a party that promises not to raise any of the three biggest taxes in the country, including income tax.

Mr. Burnham comes to the prime ministership after nearly a decade as the mayor of Greater Manchester in the north of England. The job gave him power over transport, housing, policing and skills development through adult education and training. Mr. Burnham highlighted the virtues of local over central government control as a political signature and has promised to further devolve powers from Westminster nationwide.

Britain is “extraordinarily centralized,” said Diane Coyle, a professor of public policy at the University of Cambridge who has influenced economic policymaking in Manchester for much of the past two decades.

Power, especially over finances, is hoarded in London, a level of centralization that is notable by international standards. Local governments have less ability to raise the funds they need than peer countries, according to data from the Organization for Economic Cooperation and Development, or O.E.C.D.

Centralization has led to two big, deeply entrenched problems — low growth and lagging prosperity in most of the country, and economic overheating in London and the southeast characterized by unaffordable housing. London’s productivity is 30 percent higher than Britain’s average, and it has been that way for the past couple of decades.

Here, Manchester is instructive. The city, which was an industrial powerhouse in the 19th century, suffered through the second half of the last century amid rapid deindustrialization. But it is staging a revival. The city has become a growth model with impressive amounts of inward investment and productivity gains. Mr. Burnham’s hope is that Manchester’s resurgence, the seeds of which were laid before he became mayor, can be replicated across the country.

The critical advantage of devolution, Ms. Coyle said, is officials get better information about concerns like what skills local companies need in workers, and can better sync education and training policies to meet those demands.

The recommendation was echoed by the O.E.C.D., which said on Wednesday that if Britain could shrink the gaps in regional productivity it could raise overall economic growth. Local policies could be used to get more young people into jobs and improve transportation, both major culprits in Britain’s regional inequality.

Getting there will be hard. Britain is a patchwork of local authorities, with overlapping boundaries and varying responsibilities. Some control policing. Others the collection of waste. As power has become centralized in London, the capacity to manage economic policy effectively has drained away from many parts of the country.

Britain has been left both “too fragmented and too centralized,” said Neil Lee, a professor of economic geography at the London School of Economics. Now there is a broader political consensus to try to address this, he added.

The departing government had said it was working on a plan to give local officials more control over how they spend a share of national taxes. Those efforts are in the early stages, and it remains to be seen how Mr. Burnham will carry out his vision for devolution.

Several of his other proposals are also long-term in nature. Mr. Burnham has said he will lay out a 10-year plan to bring down the cost of water, housing, energy and transportation by taking “greater public control” of these utilities and services. Given the fiscal constraints he will face, that probably means stronger regulation and more partnerships between government and companies, not widespread nationalization.

Will any of this generate economic growth? Maybe, economists say, though not quickly.

In the short term, Mr. Burnham faces a citizenry impatient for change and is expected to announce steps to tackle the cost of living.

The new government will hopefully do “a few eye-catching measures to address the cost of living,” maybe on energy prices, rent or social housing, said Danny Sriskandarajah, the chief executive of the New Economics Foundation, a think tank that has been among those advising Mr. Burnham.

The last few years have shown how the plans of Britain’s political leaders can be sent off course. The British economy is highly sensitive to shocks from events overseas because of its openness to trade and dependence on foreign bondholders.

At the start of this year, quicker economic growth and a reduction in borrowing seemed in sight, and inflation was expected to finally return to the central bank’s 2 percent target. But then the U.S. and Israeli attacks on Iran set off a war that pushed up energy prices. Household energy bills have risen on average 13 percent from a couple of months ago. Expectations of interest rate cuts, which would lower mortgage costs, have vanished.

Mr. Burnham will have to fight through these shocks to deliver his own economic agenda, including an improvement in living standards.

Otherwise, disposable incomes, adjusted for inflation, will fall, Mr. Sriskandarajah said. “And no government is going to survive that.”

China’s economy last quarter grew at the slowest rate in three years, reflecting a broader slump that the country’s leaders signaled earlier this year when they set the lowest growth target in more than three decades.

On Wednesday, the National Bureau of Statistics said that the economy expanded by 4.3 percent in the second quarter, compared to a year ago, down from a 5 percent pace in the first quarter and short of economists’ expectations.

Although China’s factories are churning out chips and electric cars to supply a global boom in artificial intelligence and energy-saving products, many Chinese people are feeling squeezed at home.

A long-running property crisis has no end in sight, with steep declines in development activity dragging down economic growth. Jobs outside of factories are hard to come by and paychecks are not growing. Retail sales of consumer goods have been choppy. They fell in May, for the first time since the end of Covid-19 lockdowns in late 2022, before recovering somewhat in June.

That is in stark contrast to China’s relentless strength in manufacturing and trade, with a government report released on Tuesday showing China’s exports surging by 27 percent in June compared with a year earlier, driven by shipments of chips, batteries and cars. China’s trade surplus in June, at more than $125 billion, was the second largest on record. In the first half of the year, the value of China’s exports grew by more than 20 percent, the data on Wednesday showed.

For economists, the latest numbers are another indication that China’s mighty export machine is masking weaknesses elsewhere.

“You get this A.I. boom, which is a global thing, and China is part of the leading nations on the frontier,” said Yu Song, the chief China economist at UBS Securities. “Without this, China’s economy would be in a much worse state.”

When measured on a quarter-to-quarter basis, China’s economy expanded by only 0.9 percent in the second quarter. When projected out for a year, the second-quarter data implies that the economy was growing at an annual rate of 3.6 percent, sharply down from a pace of more than 6 percent in the first quarter.

The second-quarter annualized rate also missed official targets. Shortcomings in China’s economic growth drivers prompted the ruling Communist Party earlier this year to set the lowest annual growth target in decades, with a goal of between 4.5 percent and 5 percent this year.

The effects of the war in Iran have put an extra squeeze on Chinese households, with rising fuel prices prompting them to drive and fly less, at a time when many were already worried about the economy and choosing to save more.

China has softened the blow of rising fuel costs by controlling the price at the pump, but the cost of filling up for drivers is still double-digit percentages higher than a year ago.

One silver lining, economists said, was that rising fuel prices started to feed through to broader inflation in the quarter, reversing a problem that China has struggled to shake: more than three years of a broad-based decline in prices. Such deflation tends to chill spending, with consumers putting off purchases in expectation that prices will be lower in the future.

China’s gross domestic product deflator, a broad measure of prices across the economy, was negative in 13 of the past 14 quarters — the most protracted slump on record. But it turned positive in the second quarter.

For China’s leadership, the question now is, what to do next? Li Qiang, China’s premier, told a group of entrepreneurs this week that officials were focusing on new drivers of consumption and ensuring job stabilization.

“It is important to take a comprehensive and objective view of ​the current economic situation, fully recognizing the achievements made while remaining cleareyed about the problems,” said Mr. Li, according to state media, which ran a story about the meeting on the front page of the official People’s Daily.

Some economists anticipate a discussion of fresh stimulus measures at a meeting of top policymakers later this month. On Monday, China’s top economic planner announced a plan to target $8.85 trillion of annual retail sales by 2030, implying a 20 percent rise from last year.

Beijing has also promised to raise wages and increase household consumption as a share of the economy. It is currently around 40 percent, significantly lower than the 60 percent share of gross domestic product for most developed countries.

But analysts said these goals are not particularly ambitious. And stubbornly reluctant consumers in China show few signs of opening their wallets.

Online shoppers are sharing tips on how to scrimp and save, rallying around the motto to “save where you can, spend where you must.”

Users have shared tips about “shopping cart cooling-off periods,” or leaving nonessential items in carts for three days before deciding to buy them. (The practice is a wry nod to the officially enforced “cooling-off period” for couples seeking divorces.)

Others push to replace foreign cosmetic brands with cheaper local alternatives, and to substitute skin care products with baby lotion. “Buy what’s right, not what’s pricey,” a user on the social media network Weibo posted recently.

All the while, prices have continued to fall for products as varied as cosmetics and automobiles. For categories like cars, the recent plunge has been accentuated by the end of a policy to incentivize purchases.

Since a devastating property crash, Chinese policymakers have tried to replace the growth generated by the real estate sector with more robust consumer spending. They rolled out huge subsidies for households to trade in old cars, home appliances and phones from 2024 through last year.

While it generated some activity, the policy failed to address the plummeting value of property, where most household wealth is concentrated. Now, economists say, China is in a “payback period” following the jump in policy-induced sales.

As the economy splits between the relatively few who benefit from China’s role in the global A.I. boom and the rest, the divide is having a profound impact on the country’s social fabric.

It has accentuated the class split between “those that benefit from the boom on their talents, well protected jobs and wealth versus those that are fully or partly replaced by A.I.,” according to economists from Nomura, a Japanese bank.

China’s property bust has led to more than 14 million people losing construction jobs. Many of those workers bought apartments in smaller cities, far from the pockets of A.I.-generated wealth that may revive parts of the property market.

“For China, the issues are that it wants to make sure it is still at the frontier,” said Mr. Song, the UBS economist. “You want the benefits to be more widely shared so that you don’t leave too many people out.”

The A.I. boom “doesn’t benefit ordinary people in China because this priority, the industrial focus on high tech and semiconductors, actually causes structural unemployment and underemployment,” said Dan Wang, the China director at Eurasia Group, a consulting firm.

What’s more, Ms. Wang said, disposable income growth is now lower than economic growth. If that continues, she noted, “that means the national income is skewed in distribution toward government and companies, and not consumers.”