What happened
Brent crude briefly traded above 97 dollars a barrel on Thursday, the highest level since late July, after United States Central Command confirmed that American forces were attacking Islamic Revolutionary Guard Corps targets inside Iran. West Texas Intermediate, the main United States benchmark, held above 92 dollars in the same session.
The move caps a violent three day run for energy markets. On Tuesday United States crude jumped 5.2 percent to settle at 90.22 dollars a barrel while Brent added 4.6 percent to close at 94.65 dollars. Two sessions later the market had added another three dollars on top of that.
Brent crude is the pricing benchmark used for roughly two thirds of the physical oil traded around the world, so a move in Brent feeds almost immediately into refinery costs across Europe and Asia. What traders are really pricing is not a shortage today but the risk of one tomorrow: the Strait of Hormuz, the narrow channel between Iran and Oman, carries close to a fifth of all seaborne crude, and insurers charge more the moment military activity moves closer to it.
Physical supply has not actually been cut. No cargo has been lost and no terminal has been shut. The entire move so far is a risk premium, which is the extra amount buyers will pay today to guarantee they hold barrels if tomorrow goes badly.
Why it matters
Oil is one of the few prices that touches almost every other price. It sets the cost of moving goods by lorry, ship and plane, it feeds into plastics, fertiliser and packaging, and it lands directly on the forecourt as petrol and diesel. A sustained ten dollar move in crude typically adds somewhere between 0.2 and 0.4 percentage points to headline inflation in an oil importing economy such as the United Kingdom.
That matters enormously right now, because British inflation is already drifting the wrong way. Consumer price inflation was 2.9 percent in July, up from 2.6 percent in June, and independent forecasters surveyed by HM Treasury expect it to reach around 3.5 percent by the final quarter of the year. Energy is precisely the channel through which that forecast becomes reality.
For the Bank of England the timing is awkward. Rate setters were beginning to feel comfortable that the inflation of the past few years had been squeezed out. A fresh energy shock resets that clock and makes it far harder to justify cutting borrowing costs, which is why interest rate futures moved against rate cuts on the same day the oil price moved up.
Companies feel it in stages. Airlines and hauliers, where fuel can be a third of operating costs, take the hit within weeks. Supermarkets and manufacturers take longer because they hedge, but they pass it on eventually. Energy producers, of course, gain: Shell and BP together make up a meaningful slice of the FTSE 100, which is part of why the London market has held up better than most this week.
Explained simply
Oil is the salt in the economic recipe. It goes into almost every dish, so when the price of salt jumps, the whole menu gets more expensive, not just the seasoning.
Start with the barrel itself. A barrel of crude is useless until it is refined, and refineries buy months ahead. When the price of the raw input rises, refineries do not absorb it, they add it to the wholesale price of petrol, diesel, jet fuel and heating oil.
Next comes the forecourt. Fuel retailers in Britain typically pass wholesale increases through over roughly four to six weeks, and they historically pass rises on faster than they pass falls back. So a jump in crude on a Thursday in September shows up at the pump in October.
Then comes everything else. The lorry that delivers to the supermarket, the ship that brought the goods to the port, the factory that heated the process, all now cost more to run. Each business faces a choice between accepting a thinner profit margin and raising prices. In practice most do a little of both, which is how one commodity price quietly becomes general inflation.
Finally the loop closes at the central bank. Rate setters cannot produce more oil, but they can cool demand for everything else so that the overall price level stays anchored. That is why an oil shock abroad can end up as a higher mortgage payment at home.
What it means for you
At the pump, expect movement. Average United Kingdom petrol prices tend to track wholesale costs with a lag of about a month, so a crude move of this size points to a rise of roughly five to eight pence a litre by mid October if Brent holds near current levels. For a driver filling a 55 litre tank weekly, that is around three to four pounds a week, or close to 200 pounds a year.
On energy bills, the effect is slower but real. The Ofgem price cap is set on a rolling assessment of wholesale gas and electricity costs, and oil and gas prices move together more often than not. A sustained crude rally raises the odds that the next cap revision goes up rather than down.
For savers and investors, the picture is mixed rather than bad. If higher oil delays interest rate cuts, easy access savings accounts currently paying around 4.0 to 4.5 percent are more likely to hold those rates through the winter rather than drift down. Cash ISA rates should behave similarly. Anyone about to remortgage, however, faces the opposite side of the same coin: fixed rate deals are priced off market expectations for future rates, and those expectations just moved higher.
If you hold a FTSE 100 tracker inside a pension or a stocks and shares ISA, you already own a large energy position whether you intended to or not. That is a genuine hedge, and it is one reason to think twice before reacting to a headline like this by reshuffling a portfolio.
The bigger picture
Markets have been here before. In March 2022 Brent spiked above 139 dollars in the weeks after the invasion of Ukraine, then spent the following year giving most of it back as demand cooled and supply rerouted. Geopolitical premiums are usually the fastest moving and the least durable part of the oil price, because they reflect fear rather than physical shortage.
What would turn this from a scare into a shock is any genuine disruption to shipping through Hormuz, or a supply cut that spare capacity elsewhere cannot cover. Spare capacity is the cushion that keeps a scare from becoming a crisis, and it is thinner than it was a decade ago.
Watch three things over the next fortnight: whether Brent holds above 95 dollars or fades back into the eighties, whether tanker insurance rates for Gulf routes keep climbing, and what the Bank of England says about energy in its policy statement on 17 September. Those three signals will tell you far more than any single day of headlines.
