What could US-Iran peace deal mean for UK household costs?

A draft peace deal between the United States and Iran has triggered a fall in global oil and gas prices, delivering immediate relief to UK motorists and raising the prospect of lower winter energy bills, though household costs remain elevated by historic standards. The price of a litre of petrol dropped by 4.6p to 155.1p this week, while diesel fell 9.3p to 175.1p, according to the AA motoring group [1]. The wholesale cost of petrol has declined by 10p a litre from the highs recorded early in the conflict [1]. Luke Bosdet of the AA attributed the speed of the reductions partly to the government’s Fuel Finder scheme, saying: “We have been surprised at the speed of the reductions and concluded that this is the influence of Fuel Finder: retailers seeing how much rivals are cutting their prices and, knowing that drivers can see the same information, having to respond.” [1] Even with the recent falls, road fuel remains expensive; before the pandemic, the Ukraine crisis, and the Iran war, the highest price British motorists had paid was 142.5p a litre [1]. The conflict had caused Brent crude oil prices to surpass $126 per barrel at their peak, with the closure of the Strait of Hormuz becoming the largest disruption to world energy supply since the 1970s energy crisis [5]. The strait was largely blocked by Iran from late February 2026 after the US and Israel launched an air war, causing tanker traffic to drop to about zero [5]. The International Energy Agency characterized the disruption as the "largest supply disruption in the history of the global oil market" [2]. Europe’s gas prices have also fallen, from more than €61 per megawatt-hour in the first month of the war to between €40 and €42/MWh this week [1]. The conflict coincided with historically low European gas storage levels, estimated at just 30% capacity following a harsh 2025–2026 winter, causing Dutch TTF gas benchmarks to nearly double to over €60/MWh by mid-March [2]. Households in England, Scotland, and Wales are still bracing for a 13% rise in energy rates for the July to September period, lifting the typical annual bill to £1,862 [1]. However, recent declines in wholesale gas costs mean the price cap from October to the end of the year is likely to be lower, as the regulator Ofgem bases its calculations on a later trading window [1]. In the mortgage market, swap rates now suggest no more than one base rate rise in the second half of 2026, according to Lorna Hopes, a mortgage specialist at Smith & Pinching [1]. Nationwide and Barclays have cut their mortgage rates in recent days, but the best two-year fix remains near 4.49%, compared with 3.69% in February [1]. Nicholas Mendes of broker John Charcol noted: “Borrowers are still paying more than they were in February, and it’s a meaningful gap, even with the cuts that have come through lately.” [1] Tesco chief executive Ken Murphy said he did not expect grocery inflation to reach the 9% levels suggested by some industry bodies early in the war, particularly as pump prices were falling [1]. The draft deal was signed by Donald Trump, whose administration launched the attack on Iran in February 2026 with the stated goal of regime change [3]. The subsequent Strait of Hormuz crisis stranded Qatari LNG exports and forced QatarEnergy to declare force majeure on all exports [2].