When Donald Trump signed a draft peace agreement with Iran last week, the instrument that moved fastest was not a diplomatic cable but a price ticker. Crude oil, which had surged above $126 a barrel during the most acute phase of the crisis — when Iran's effective blockade of the Strait of Hormuz severed a critical artery of global energy supply — has now fallen below $80. European natural gas prices have retreated from more than €61 per megawatt-hour in the first month of the conflict to between €40 and €42 per MWh this week, a decline of roughly a third that reflects how quickly financial markets can reprice geopolitical risk. At British petrol stations, that repricing is beginning to show in tangible form.

According to the AA motoring group, the price of a litre of petrol dropped by 4.6p between 28 May and this week — from 159.7p to 155.1p — while diesel fell a more pronounced 9.

3p, from 184.4p to 175.1p per litre. The AA's Luke Bosdet credited part of that speed to the government's Fuel Finder comparison scheme, launched in February, which forces retailers to respond visibly to rivals' cuts.

"We have been surprised at the speed of the reductions and concluded that this is the influence of Fuel Finder," Bosdet said. Nevertheless, wholesale petrol costs remain roughly 10p per litre above pre-crisis levels, and the AA cautioned that lingering Gulf supply-chain disruption would keep forecourt prices elevated relative to their longer historical range. Before the successive shocks of Covid-19, the Ukraine war, and the Iran conflict, British drivers had never paid more than 142.5p a litre.