What happened
Brent crude futures settled at 100.49 dollars a barrel on Wednesday, up more than 2.5 per cent and above the 100 dollar mark for the first time in more than a year. Brent crude is the benchmark grade used to price roughly two thirds of the oil traded worldwide, so when Brent moves, fuel bills across Europe move with it. West Texas Intermediate, the American benchmark, rose about 2.3 per cent to 95.09 dollars.
The trigger was a sharp escalation between Washington and Tehran. US forces destroyed five Iranian oil tankers near Kharg Island, the terminal that handles the large majority of Iranian crude exports. Iran retaliated with missile strikes in Jordan, widening a confrontation that traders had until recently treated as contained to shipping lanes.
The move caps a fast climb. Brent closed at 98.00 dollars on Tuesday, its highest level since 23 July, after Saudi Arabia confirmed that attacks by Houthi forces had halted operations at several energy facilities. Two separate supply shocks landing within days of each other left the market with very little slack to price against.
Equity markets read the news as bad news for growth. Asian indices fell across the board, with the Nikkei 225 down 0.3 per cent, the Shanghai Composite off 0.1 per cent and the Hang Seng lower by 0.5 per cent. Energy producers were the exception, rising on the prospect of fatter margins.
Why it matters
Oil is not just a commodity that some people trade. It is an input into almost everything that has to be grown, made, chilled, packaged or moved. A 100 dollar barrel raises the cost of running a delivery van, heating a warehouse, making fertiliser and flying a plane, all at once.
That is why central bankers watch the oil price so closely. The Bank of England has already signalled that the risks to UK inflation are tilted upwards because of Middle East energy prices, with Bank Rate sitting at 3.75 per cent and the central projection showing consumer price inflation peaking near 3.2 per cent in the final quarter of 2026. A sustained triple digit barrel makes that peak higher and later.
Britain imports a large share of the crude and refined fuel it consumes, so a higher barrel price is a transfer of money out of the country. Households pay more, businesses pay more, and the cash goes to producers abroad rather than circulating at home. Economists call this a terms of trade shock, and it acts on the economy much like a tax rise nobody voted for.
There is also a distributional edge to it. Fuel and heating take up a far larger share of the budget for lower income households than for higher income ones, so an energy shock is regressive even before any policy response.
Explained simply
Think of the oil market as a bathtub with the taps only just keeping pace with the drain. Knock out one tap and the level does not dip a little, it drops fast, because there was never much spare water to begin with.
Global oil demand runs at roughly 103 million barrels a day. Spare capacity, meaning the barrels producers could bring online quickly if they had to, is a thin cushion of a few million barrels. When a couple of million barrels of supply are threatened at once, the price does not move in proportion to the loss. It jumps, because buyers who absolutely must have fuel bid against each other for what is left.
The second thing to understand is that oil prices are set in futures markets, meaning contracts to deliver oil at a set price on a future date. Traders are not pricing the barrels sitting in a tank today. They are pricing what they think supply will look like in three months. So the price can spike on the risk of disruption long before a single litre goes missing from a forecourt.
Finally, the journey from barrel to pump has a lag and a floor. Refiners buy crude, turn it into petrol and diesel, and sell it on. In the UK, fuel duty and VAT make up a large chunk of the pump price, which cushions the percentage move. A 10 per cent rise in crude usually shows up as something closer to a 4 to 5 per cent rise at the pump, and it typically takes two to six weeks to arrive.
What it means for you
Start with the car. Petrol has been averaging around 138 pence a litre in the UK. If Brent holds near 100 dollars, forecourt prices could reasonably add 5 to 8 pence a litre over the next month or so. On a 55 litre fill, that is roughly 3 to 4.50 pounds each time you fill up, or about 15 to 25 pounds a month for an average commuter.
Next, heating. Wholesale gas and oil prices are linked, and the Ofgem energy price cap resets quarterly using wholesale prices from an earlier reference window. That means a shock now feeds into bills in a later cap period rather than immediately, but it does feed through. If you are on a variable tariff and a fixed deal is available within a few per cent of the current cap, this is a reasonable moment to run the comparison.
For investors, the effect is uneven. The FTSE 100 has heavy weightings in Shell and BP, so a UK tracker fund actually gets some protection from an oil shock in a way that a global technology heavy fund does not. Airlines, cruise operators, hauliers and retailers with long supply chains sit on the losing side.
If you hold a workplace pension in a default global fund, resist the urge to act. Energy shocks are noisy and mean reverting, and the historical record for retail investors trading around geopolitics is poor.
The bigger picture
Oil has crossed 100 dollars three times this century in response to conflict, most recently in 2022 after the invasion of Ukraine. Each time the immediate spike was followed by demand destruction, as expensive fuel persuaded people to drive less and businesses to economise, which eventually pulled prices back down. The question is how long the round trip takes.
The variable to watch is the Strait of Hormuz, the narrow channel through which roughly a fifth of the seaborne oil trade passes. Disruption to shipping through the strait, rather than damage to any single facility, is what turns a price spike into a genuine shortage. Insurance premiums on tankers transiting the region are the earliest indicator that the market has moved from worrying to rerouting.
Also watch OPEC. The producer group has been holding barrels back to support prices. A decision to release spare capacity would be the fastest way to cool the market, and would also be a signal that the group fears a demand collapse more than it wants a high price.
