If you ever fly to Washington DC, look out of the window as you land at Dulles Airport – and you might snatch a glimpse of the single biggest story in economics right now.
There below you, you will see scattered around the fields and woods of the local area a set of vast warehouses that might to the untrained eye look like supermarkets or distribution centres. But no: these are in fact data centres – the biggest concentration of data centres anywhere in the world.
For this area surrounding Dulles Airport has more of these buildings, housing computer servers that do the calculations to train and run artificial intelligence (AI), than anywhere else. And since AI accounts for the vast majority of economic growth in the US so far this year, that makes this place an enormous deal.
Down at ground level you can see the hallmarks as you drive around what is known as “data centre alley”. There are enormous power lines everywhere – a reminder that running these plants is an incredibly energy-intensive task.
This tiny area alone, Loudoun County, consumes roughly 4.9 gigawatts of power – more than the entire consumption of Denmark. That number has already tripled in the past six years, and is due to be catapulted ever higher in the coming years.
Inside ‘data centre alley’
We know as much because we have gained rare access into the heart of “data centre alley”, into two sites run by Digital Realty, one of the biggest datacentre companies in the world. It runs servers that power nearly all the major AI and cloud services in the world. If you send a request to one of those models or search engines there’s a good chance you’ve unknowingly used their machines yourself.
Image: Inside a site run by Digital Realty
Their Digital Dulles site, under construction right now, is due to consume up to a gigawatt in power all told, with six substations to help provide that power. Indeed, it consumes about the same amount of power as a large nuclear power plant.
Walking through the site, a series of large warehouses, some already equipped with rows and rows of backup generators, there to ensure the silicon chips whirring away inside never lose power, is a striking experience – a reminder of the physical underpinnings of the AI age. For all that this technology feels weightless, it has enormous physical demands. It entails the construction of these massive concrete buildings, each of which needs enormous amounts of power and water to keep the servers cool.
We were given access inside one of the company’s existing server centres – behind multiple security cordons into rooms only accessible with fingerprint identification. And there we saw the infrastructure necessary to keep those AI chips running. We saw an Nvidia DGX H100 running away, in a server rack capable of sucking in more power than a small village. We saw the cooling pipes running in and out of the building, as well as the ones which feed coolant into the GPUs (graphic processing units) themselves.
Such things underline that to the extent that AI has brainpower, it is provided not out of thin air, but via very physical amenities and infrastructure. And the availability of that infrastructure is one of the main limiting factors for this economic boom in the coming years.
According to economist Jason Furman, once you subtract AI and related technologies, the US economy barely grew at all in the first half of this year. So much is riding on this. But there are some who question whether the US is going to be able to construct power plants quickly enough to fuel this boom.
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2:08
Is Trump’s AI plan a ‘tech bro’ manifesto?
For years, American power consumption remained more or less flat. That has changed rapidly in the past couple of years. Now, AI companies have made grand promises about future computing power, but that depends on being able to plug those chips into the grid.
Last week the International Monetary Fund’s chief economist, Pierre-Olivier Gourinchas, warned AI could indeed be a financial bubble.
He said: “There are echoes in the current tech investment surge of the dot-com boom of the late 1990s. It was the internet then… it is AI now. We’re seeing surging valuations, booming investment and strong consumption on the back of solid capital gains. The risk is that with stronger investment and consumption, a tighter monetary policy will be needed to contain price pressures. This is what happened in the late 1990s.”
‘The terrifying thing is…’
For those inside the AI world, this also feels like uncharted territory.
Helen Toner, executive director of Georgetown’s Center for Security and Emerging Technology, and formerly on the OpenAI board, said: “The terrifying thing is: no one knows how much further AI is going to go, and no one really knows how much economic growth is going to come out of it.
“The trends have certainly been that the AI systems we are developing get more and more sophisticated over time, and I don’t see signs of that stopping. I think they’ll keep getting more advanced. But the question of how much productivity growth will that create? How will that compare to the absolutely gobsmacking investments that are being made today?”
Whether it’s a new industrial revolution or a bubble – or both – there’s no denying AI is a massive economic story with massive implications.
For energy. For materials. For jobs. We just don’t know how massive yet.
The Bank of England has warned of heightened risks to the UK’s financial system but cut the amount of money that banks need to hold in reserve in case of shock.
The twice-yearly financial stability report highlights a series of pressures, from higher government borrowing costs to risks around lending to major tech firms and record stock market valuations – particularly in areas exposed to artificial intelligence (AI).
“Risks to financial stability have increased during 2025,” the Bank‘s financial policy committee (FPC) said.
“Global risks remain elevated and material uncertainty in the global macroeconomic outlook persists. Key sources of risk include geopolitical tensions, fragmentation of trade and financial markets, and pressures on sovereign debt markets.
“Elevated geopolitical tensions increase the likelihood of cyberattacks and other operational disruptions.
“In the FPC’s judgement, many risky asset valuations remain materially stretched, particularly for technology companies focused on AI.
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“Equity valuations in the US are close to the most stretched they have been since the dot-com bubble, and in the UK since the global financial crisis (GFC). This heightens the risk of a sharp correction.”
Its concern extended to the growing trend of tech firms using debt finance to fund investment.
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1:11
Could the AI bubble burst?
The Bank, which joined the International Monetary Fund in warning over an AI-led bubble in October, delivered its verdict at a time when UK regulators are under pressure from the government to place a greater focus on supporting economic growth.
It is understood, for example, the UK’s ringfencing regime – that sees retail banking separated from more risky investment banking operations within major lenders – is the subject of a review between the Bank and government.
Efforts by the chancellor to grow the economy will be potentially helped by the Bank’s decision today to lower capital requirements – the reserves banks must hold to help them withstand shocks in the financial system such as the global crisis of 2008/9.
The sector’s main capital requirement was cut by the Bank from 14% to 13%.
Image: The Bank said that almost four million households face higher mortgage costs as fixed-term deals end. Pic: iStock
Such a move was urged, not only by the government, but by businesses to bolster UK lending and competitiveness.
The relaxation of the buffer does not take effect until 2027.
It was announced alongside confirmation that the country’s biggest lenders – Barclays, HSBC, Lloyds, NatWest, Santander UK, Standard Chartered and Nationwide building society – had passed the Bank’s latest stress tests.
The shocks each was exposed to included a 5% contraction in UK economic output, a 28% drop in house prices and Bank rate at 8%.
Despite the growing risks identified by the FPC, the Bank said that each was strong enough to support households and businesses even in the event of such scenarios, given the healthy state of their reserves.
It is widely expected that the gradual reduction in Bank rate will continue next year, assuming the outlook for inflation remains on a downwards trajectory, helping wider borrowing costs – a source of record bank profitability – decline.
The Bank said that three million households were expected to see their mortgage payments decrease in the next three years but that 3.9 million were forecast to refinance onto higher rates.
As such, it projected a £64 (8%) rise in costs for a typical owner-occupier mortgage customer rolling off a fixed rate deal in the next two years.
Banking stocks, which have enjoyed strong gains this year, were up when the FTSE 100 opened for business despite wider market caution globally which is aligned with the risks spoken of in the financial stability report.
Matt Britzman, senior equity analyst at Hargreaves Lansdown, said: “UK banks are offering a dose of optimism this morning in what’s turning out to be a good couple of weeks for the major lenders.
“The UK’s seven biggest banks sailed through the latest stress test, reaffirming their resilience and earning a regulatory nod to ease capital buffers.
“Most banks already hold capital well above the minimum by choice, so any shift in strategy may take time – but in theory, it frees up extra capital for lending or capital returns.
“However they use the new freedom, this is another clear signal that the UK banking sector is in robust health. This was largely expected, but the confirmation should still be taken well, especially after dodging tax hikes in last week’s budget.”
Did the chancellor mislead the public, and her own cabinet, before the budget?
It’s a good question, and we’ll come to it in a second, but let’s begin with an even bigger one: is the prime minister continuing to mislead the public over the budget?
The details are a bit complex but ultimately this all comes back to a rather simple question: why did the government raise taxes in last week’s budget? To judge from the prime minister’s responses at a news conference just this morning, you might have judged that the answer is: “because we had to”.
“There was an OBR productivity review,” he explained to one journalist. “The result of that was there was £16bn less than we might otherwise have had. That’s a difficult starting point for any budget.”
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3:29
Beth Rigby asks Keir Starmer if he misled the public
Time and time again throughout the news conference, he repeated the same point: the Office for Budget Responsibility had revised its forecasts for the UK economy and the upshot of that was that the government had a £16bn hole in its accounts. Keep that figure in your head for a bit, because it’s not without significance.
But for the time being, let’s take a step back and recall that budgets are mostly about the difference between two numbers: revenues and expenditure; tax and spending. This government has set itself a fiscal rule – that it needs, within a few years, to ensure that, after netting out investment, the tax bar needs to be higher than the spending bar.
At the time of the last budget, taxes were indeed higher than current spending, once the economic cycle is taken account of or, to put it in economists’ language, there was a surplus in the cyclically adjusted current budget. The chancellor had met her fiscal rule, by £9.9bn.
Image: Pic: Reuters
This, it’s worth saying, is not a very large margin by which to meet your fiscal rule. A typical budget can see revisions and changes that would swamp that in one fell swoop. And part of the explanation for why there has been so much speculation about tax rises over the summer is that the chancellor left herself so little “headroom” against the rule. And since everyone could see debt interest costs were going up, it seemed quite plausible that the government would have to raise taxes.
Then, over the summer, the OBR, whose job it is to make the official government forecasts, and to mark its fiscal homework, told the government it was also doing something else: reviewing the state of Britain’s productivity. This set alarm bells ringing in Downing Street – and understandably. The weaker productivity growth is, the less income we’re all earning, and the less income we’re earning, the less tax revenues there are going into the exchequer.
The early signs were that the productivity review would knock tens of billions of pounds off the chancellor’s “headroom” – that it could, in one fell swoop, wipe off that £9.9bn and send it into the red.
That is why stories began to brew through the summer that the chancellor was considering raising taxes. The Treasury was preparing itself for some grisly news. But here’s the interesting thing: when the bad news (that productivity review) did eventually arrive, it was far less grisly than expected.
True: the one-off productivity “hit” to the public finances was £16bn. But – and this is crucial – that was offset by a lot of other, much better news (at least from the exchequer’s perspective). Higher wage inflation meant higher expected tax revenues, not to mention a host of other impacts. All told, when everything was totted up, the hit to the public finances wasn’t £16bn but somewhere between £5bn and £6bn.
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8:46
Budget winners and losers
Why is that number significant? Because it’s short of the chancellor’s existing £9.9bn headroom. Or, to put it another way, the OBR’s forecasting exercise was not enough to force her to raise taxes.
The decision to raise taxes, in other words, came down to something else. It came down to the fact that the government U-turned on a number of its welfare reforms over the summer. It came down to the fact that they wanted to axe the two-child benefits cap. And, on top of this, it came down to the fact that they wanted to raise their “headroom” against the fiscal rules from £9.9bn to over £20bn.
These are all perfectly logical reasons to raise tax – though some will disagree on their wisdom. But here’s the key thing: they are the chancellor and prime minister’s decisions. They are not knee-jerk responses to someone else’s bad news.
Yet when the prime minister explained his budget decisions, he focused mostly on that OBR report. In fact, worse, he selectively quoted the £16bn number from the productivity review without acknowledging that it was only one part of the story. That seems pretty misleading to me.
Sir Keir Starmer has denied he and the chancellor misled the public and the cabinet over the state of the UK’s public finances ahead of the budget.
The prime minister told Sky News’ political editor Beth Rigby “there was no misleading”, following claims he and Rachel Reeves deliberately said public finances were in a dire state, when they were not.
He said a productivity review by the Office for Budget Responsibility (OBR), which provides fiscal forecasts to the government, meant there would be £16bn less available so the government had to take that into account.
“To suggest that a government that is saying that’s not a good starting point is misleading is wrong, in my view,” Sir Keir said.
Cabinet ministers have said they felt misled by the chancellor and prime minister, who warned public finances were in a worse state than they thought, so they would have to raise taxes, including income tax, which they had promised not to in the manifesto.
At last Wednesday’s budget, Ms Reeves unveiled a record-breaking £26bn in tax rises.
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The OBR published the forecasts it provided to the chancellor in the two months before the budget, which showed there was a £4.2bn headroom on 31 October – ahead of that warning about possible income tax rises on 4 November.
Image: The OBR’s timings and outcomes of the fiscal forecasts reported to the Treasury
Sir Keir added: “There was a point at which we did think we would have to breach the manifesto in order to achieve what we wanted to achieve.
“Late on, it became possible to do it without the manifesto breach. And that’s why we came to the decisions that we did.”
Sir Keir said a productivity review had not taken place in 15 years and questioned why it was not done at the end of the last government, as he blamed the Conservatives for the OBR downgrading medium-term productivity growth by 0.3 percentage points to 1% at the end of the five-year forecast.
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0:58
Reeves: I didn’t lie about ‘tax hikes’
The prime minister added: “I wanted to more than double the headroom, and to bear down on the cost of living, because I know that for families and communities across the country, that is the single most important issue, I wanted to achieve all those things.
“Starting that exercise with £16 billion less than we might otherwise have had. Of course, there are other figures in this, but there’s no pretending that that’s a good starting point for a government.”
On Sunday, when asked by Sky’s Trevor Phillips if she lied, Ms Reeves said: “Of course I didn’t.”
She also said the OBR’s downgrade of productivity meant the forecast for tax receipts was £16bn lower than expected, so she needed to increase taxes to create fiscal headroom.