Britain joined France, Germany, Italy, the Netherlands and Japan on 19 March in condemning Iranian attacks on shipping and energy sites, warning that the Strait of Hormuz is effectively closed and urging Tehran to comply with UN Security Council Resolution 2817. The statement welcomes an International Energy Agency (IEA) move to release emergency oil stocks and signals readiness to support safe passage; it was updated on 20 March to record further countries joining. (gov.uk) For UK readers, this is not just geopolitics-it's a supply and inflation story. The text explicitly frames interference with shipping and energy infrastructure as a threat to global peace and security, and flags measures to stabilise markets, including working with producers to lift output. (gov.uk)

Why does Hormuz matter? The IEA says roughly 20 million barrels per day transited the strait in 2025-about a quarter of seaborne oil. Today, export volumes are running at under 10% of pre‑conflict levels, according to the Agency. UK‑facing supply chains feel this via higher crude, pricier freight and delayed cargoes. (iea.org) Independent tracking backs up the slowdown. The Joint Maritime Information Center reported a near‑total halt at points in early March, while Lloyd’s List Intelligence counted just 89 crossings between 1–15 March versus a typical 100–135 passages a day before the war. (insurancejournal.com)

Markets have reacted fast. Brent flirted with $100 on 9 March and major houses have been revising forecasts upward. The US Energy Information Administration now expects Brent to trade above $95 over the next two months, while UBS has raised its first‑quarter and full‑year 2026 projections, citing the near closure of Hormuz. (moneyweek.com) This is the classic energy price shock playbook: tighter physical supply, a fatter risk premium and higher volatility. For investors, the path from crude to CPI is not instant-but it is direct.

The IEA’s emergency response is sizeable. Member countries have authorised the release of 400 million barrels from strategic reserves-the largest on record and more than double the 182.7 million barrels coordinated in 2022 after Russia’s full‑scale invasion of Ukraine. Implementation will vary by country, and details on pace will follow. (iea.org) IEA chief Fatih Birol has also warned that the paralysis of Hormuz amounts to the greatest energy‑security threat in modern history-underlining why stocks are being used now. (lemonde.fr)

Insurance is now a cost centre in its own right. Several Protection & Indemnity (P&I) clubs cancelled war‑risk cover for Gulf waters with effect from 5 March, forcing owners onto specialist war policies. Premiums have jumped-up to 1% of a vessel’s hull value in recent days, from around 0.2% the week before-adding hundreds of thousands of dollars to a single tanker voyage. (aljazeera.com) Lloyd’s of London says cover remains available, but at higher rates aligned to the risk. In parallel, Washington has floated insurance backstops alongside potential escorts-signals meant to coax ships back into the corridor. (theguardian.com)

For UK drivers, the pressure is already visible at the pump. MoneyWeek, citing RAC Fuel Watch, reports average petrol rose by 9.5p between 28 February and 17 March to 142.29p per litre, with diesel up 19.7p to 162.06p over the same period. The RAC has warned that if oil holds near $100, pump prices are likely to climb further. (moneyweek.com) That feeds directly into headline inflation. The Bank of England held Bank Rate at 3.75% on Thursday, noting that the oil and gas spike after the Iran war began had complicated the disinflation path. (apnews.com)

Gas is part of the story too. With shipping through Hormuz disrupted, Qatar-normally supplying close to a fifth of global LNG-has seen exports halted, prompting force‑majeure notices and driving up European benchmark prices. S&P Global calls it an unprecedented near‑term shock; Bloomberg data show Qatar’s export pause has been the longest since at least 2008. (spglobal.com) Ofgem’s Q1 cap is already set, but analysts caution that a prolonged disruption raises summer bill risks if wholesale gas remains elevated. (moneyweek.com)

For small firms, higher fuel costs mean tighter margins and tougher logistics. Expect surcharges from hauliers and freight forwarders, plus longer lead times on Gulf‑sourced inputs. Cash‑flow planning over the next eight weeks should assume stickier diesel prices and potential delivery slippage if war‑risk underwriting remains restrictive. Evidence from insurers and brokers points to ongoing caution in the market. (theguardian.com)

Diplomacy is moving, but slowly. The UK‑led statement notes a readiness to support safe passage and has since drawn additional signatories, while allied capitals debate how far to go on escorts. Reporting from Axios indicates support in principle for a coalition to reopen the strait, though several European partners have stopped short of troop commitments; France has floated escorts only when hostilities ebb. (gov.uk) In the meantime, traffic remains sparse and risk premiums elevated-conditions that typically keep a floor under energy prices.

What to watch next: three signposts will set the tone for UK costs. First, clarity on the IEA release schedule-volumes per month matter for pricing. Second, whether producers can lift output that actually reaches market; OPEC+ has signalled a modest 206,000 bpd increase from April, but pipeline capacity and export routes limit what bypasses Hormuz. Third, central‑bank reactions if energy inflation persists. (iea.org) For now, the policy mix is to keep energy flowing and calm prices. The UK statement makes that explicit; the market will judge it by how quickly ships, and then premiums, return to something like normal. (gov.uk)