On Thursday, Brent crude, the global oil benchmark, climbed by 5% to reach $105.3 a barrel. The jump was triggered by two forces converging at once: a report that the White House had asked the Pentagon to prepare strike options against Iran before next month's US midterm elections, and a hurricane bearing down on the Gulf of Mexico that forced Shell and Chevron to halt production. Within hours, the tremor had travelled from the Strait of Hormuz to bond desks in London.

The clearest sign of nervousness came from British government debt. The yield on the UK's 10-year bond, which moves inversely to its price, rose six basis points to 5.515%, a level last seen in July 2007. The 30-year bond, which sets the benchmark cost of Britain's long-term borrowing, climbed to 6.

0117%, having touched 6.036% a day earlier — its highest point since January 1998. Investors, it seems, are betting that costlier oil will keep inflation elevated for longer, forcing central banks to hold interest rates up rather than cut them. The timing is awkward for John Healey, who must deliver his first budget on 28 October while borrowing costs climb around him.

Meanwhile, the war between the US and Israel on one side and Iran on the other, now in its eighth month, has pushed attacks on tankers in the Strait of Hormuz to their highest frequency yet; a vessel was struck off Qatar's coast on Wednesday, according to UK Maritime Trade Operations. Danish shipping giant Maersk has already responded by raising fuel surcharges on its global routes.