Iran has reinstated restrictions on the Strait of Hormuz, sending oil prices higher and pushing the FTSE 100 into the red on 20 April 2026. With the US-Iran ceasefire deadline expiring this week and reports that the US has seized an Iranian-flagged vessel in the Gulf of Oman, markets are pricing in a new phase of the conflict — and UK households should expect the consequences to feed through into fuel, energy and borrowing costs again.
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⚠ Breaking — 20 April 2026 • Iran reinstated Strait of Hormuz restrictions after the US refused to lift its blockade of Iranian ports • US forces seized an Iranian-flagged cargo vessel in the Gulf of Oman over the weekend • US-Iran ceasefire agreement expires this week • Brent crude back above 100 dollars a barrel • FTSE 100 closed lower, pulling back from a six-week high • European equities fell broadly as oil prices climbed |
What happened over the weekend
The Strait of Hormuz — the narrow waterway between Iran and Oman through which roughly 20% of global seaborne oil flows — had been partially reopened in recent weeks under the terms of the US-Iran ceasefire. That arrangement is unravelling. Tehran has announced reinstated restrictions on passage, citing what it calls the continuing US blockade of Iranian ports. Washington responded by seizing an Iranian-flagged vessel in the Gulf of Oman.
The net effect is that the ceasefire is functionally over even before its formal expiry. Markets reacted immediately on Monday morning.
What moved on 20 April
| Asset | Move | What it signals |
|---|---|---|
| Brent crude | Up; back above $100 | Supply risk premium re-entering prices |
| FTSE 100 | Closed lower | Retreat from six-week high; broad risk-off |
| European equities | Broadly lower | Hormuz closure fears amplified across region |
| US indices | Lower at open | Vessel seizure pushed risk appetite down |
| Sterling | Mixed | Growth concerns offset oil-importer penalty |
Why Hormuz matters so much
Around 20% of global oil and a significant share of liquefied natural gas passes through the Strait of Hormuz. Qatar, one of the UK's major LNG suppliers, ships nearly all of its gas through the waterway. When transit is disrupted, the effect is not just higher headline oil prices — it is also tighter global gas supply, which matters enormously for the UK because domestic electricity prices are still tied to the marginal gas price.
Since the conflict began on 28 February 2026, oil has moved from around 70 dollars to over 100 dollars a barrel. Cornwall Insight forecasts that the July 2026 energy price cap will rise to £1,972.53 — a 20%-plus jump from the April cap of £1,641. The Ofgem announcement is due on 27 May, and every day of Hormuz disruption between now and then locks more of that rise in.
What this means for UK households this week
Fuel prices
Petrol and diesel respond quickly to Brent crude movements — typically within a week or two, as existing refinery stocks cycle through. Expect forecourt prices to tick up over the next fortnight if crude holds above 100 dollars.
Energy bills
The April price cap is already locked at £1,641. The July cap will be set based on wholesale prices from 18 February to 17 May. Every day of sustained high prices pulls the July number higher. Cornwall Insight's latest forecast is around £1,929 for July; EDF sees £1,937; earlier projections went to £1,972. The Ofgem announcement on 27 May will be the real number.
Mortgages
Gilt yields rose on the weekend news. Fixed-rate mortgages are priced off swap rates and gilts. A sustained move higher in yields will feed through to new fixed products within days — some lenders reprice faster than others. Around one million fixed-rate deals expire between April and September 2026; if yours is one of them, the pipeline for securing a new rate is narrowing.
Supermarket food
Higher energy costs push production, distribution and cold-chain costs up. Industry groups have warned that food price rises of up to 10% are possible in the second half of 2026 if energy prices stay where they are. That is a direct, visible hit to household budgets.
The 30 April Bank of England meeting
The MPC was already unanimously at "hold" mode. Today's news strengthens that case. Around 90% of Reuters-polled economists expect the Bank to leave the base rate at 3.75% on 30 April. A small but rising minority of forecasters now see the possibility of a hike before year-end if the conflict escalates meaningfully.
The Bank cannot control oil prices. What it can do is ensure that higher energy costs do not translate into persistently higher wage settlements and corporate pricing — the so-called second-round effects. That is the scenario most likely to trigger a rate hike rather than a cut.
Where this could go from here
Best case
A renewed ceasefire agreement within days, Hormuz shipping returning to near-normal by early May, and oil sliding back toward 80 dollars. In that scenario the July price cap rise still happens but is smaller; the Bank holds in April and quite possibly cuts in Q3.
Base case
Disrupted but not closed shipping, oil hovering at 95 to 105 dollars through the summer. The July cap rises as forecast; the Bank holds through 2026; fixed mortgage rates stay near current levels.
Downside case
Full or extended closure of Hormuz, oil spiking above 120 dollars, LNG contracts disrupted. The July and October caps rise substantially; the Bank may be forced to hike; mortgage costs rise further; food inflation materialises.
Disclaimer
This article reflects market conditions as of 20 April 2026 and may be overtaken by events rapidly. It is information, not trading or financial advice. Geopolitical situations change quickly; figures quoted can move within hours.
Frequently asked questions
How long did the previous Hormuz closures last?
Iran first announced closure on 2 March 2026. Passage has been partially restored, partially restricted, and now restricted again. No complete sustained closure has occurred, but the uncertainty itself keeps risk premiums embedded in prices.
Does the UK import oil directly from Iran?
No. UK direct imports from Iran are effectively zero. The effect on the UK is entirely through global prices — and through LNG supply from Qatar, which does transit Hormuz.
Should I fix my energy tariff now?
With Cornwall Insight forecasting the July cap at close to £1,972 — roughly 20% above April — any fixed deal priced meaningfully below that for 12 months deserves a serious look. Martin Lewis has previously suggested fixes priced up to around 11% above the January 2026 cap (roughly £1,952) are likely to save money over a 12-month horizon at current forecasts.
What about the stock market?
Equity markets are forward-looking. Today's fall reflects the market pricing in a worse conflict outcome than it was assuming last week. If the situation calms, markets will typically rebound faster than the real economy does. If it escalates further, the opposite.
The bottom line
The reinstated Hormuz restrictions and US vessel seizure mark an escalation at precisely the moment markets had started to believe the worst was over. UK households should budget for a meaningfully higher July energy cap, sustained-high mortgage rates, and at least some food price pressure through the second half of 2026. The situation is fluid; the Bank of England's 30 April decision is the next major checkpoint.
