Britain's Food Larder Meets the Strait of Hormuz: Inside Whitehall's Worst-Case Plans

Ministers, supermarket chief executives and senior civil servants are rehearsing a scenario they insist is only a precaution: that by summer, the war between Iran, Israel and the United States has still not produced a ceasefire, the Strait of Hormuz remains closed to commercial shipping, and Britain's sprawling, just-in-time food supply chain begins to fray at its seams. A leaked Whitehall planning exercise, briefings from the Business Secretary, and warnings from the National Farmers' Union, the Food and Drink Federation and major grocers have converted what began as a geopolitical story into a domestic one about bread, cooking oil, glasshouse tomatoes and the carbon dioxide used to stun pigs at slaughter.

What emerges from the leaks and the public statements is neither the sort of panic that marked the opening weeks of the pandemic nor the reassurance ministers would prefer. It is a more precise anxiety: that specific inputs — fertiliser, diesel, CO2, cooking oils, nitrogen — could choke at specific pinch-points, that food inflation could run to double digits, and that the households least able to absorb those costs are already using food banks in record numbers.

What the Government Is Actually Planning For

The central document is an internal contingency exercise codenamed Exercise Turnstone, drawn up by officials in Downing Street, the Treasury and the Ministry of Defence and rehearsed by the Cabinet's emergency committee, COBRA [1][2]. The exercise assumes that by June 2026 the Strait of Hormuz has not reopened and that no permanent peace deal has been reached [2]. Under that reasonable worst-case, carbon dioxide supplies — used to slaughter pigs and poultry, to preserve packaged meat and salads, and to carbonate drinks — could fall to roughly 18% of current levels [1][2].

Government lawyers have been asked to prepare the machinery for invoking the Civil Contingencies Act 2004, which would let ministers make emergency regulations by order, direct industrial output, relax competition rules so that scarce CO2 could be channelled to healthcare and food processors, and, if needed, introduce statutory allocation of supplies [1][3]. Ministers have already announced that the Ensus bioethanol plant on Teesside will restart for at least three months to boost domestic CO2 production, a step that mirrors the bailout negotiated during the 2021 fertiliser-price shock [4].

Business Secretary Peter Kyle said publicly that the Prime Minister has chaired the COBRA process from the outset and that the planning is intended to "reassure" households rather than alarm them, describing the worst-case modelling as standard scenario work rather than a forecast [5]. Tesco's chief executive confirmed the supermarket is in "constant contact" with the government and had not yet seen problems with suppliers, while warning investors that the conflict is creating uncertainty for the outlook [6].

The Shipping Choke-Point and the Commodities at Risk

The conflict itself began on 28 February 2026, when the United States and Israel launched a coordinated air campaign against Iran; Iran retaliated against regional US bases, Gulf energy infrastructure, and shipping in the Strait of Hormuz [7]. Tanker traffic through the strait has since fallen by more than 90% [7], and industry bodies estimate that roughly 2,000 vessels are held up across the wider region carrying grains, edible oils, sugar, cocoa and fertiliser [8].

The crude-oil price has been the clearest barometer. The US benchmark, West Texas Intermediate, rose above $114 a barrel in the weeks after the strikes began, before settling around $100 in mid-April — roughly 62% above the same point a year earlier [9].

Source: FRED / EIA

Data as of Apr 13, 2026CSV

That matters for food for three linked reasons. First, diesel and red diesel are the backbone of UK farm operations; the price of red diesel has risen by roughly 60% since the strikes began, according to the NFU [10]. Second, around a third of global fertiliser trade moves through the strait, and the UK imports roughly 60% of its nitrogen fertiliser [8]. Third, ammonia and urea prices — the building blocks of synthetic fertiliser — are tightly linked to natural gas, and Qatar supplies between 12% and 14% of Europe's liquefied natural gas through the same chokepoint [11].

The commodities most exposed on British shelves are therefore not exotic: sunflower and rapeseed oils routed through Gulf ports, long-grain rice from South and Southeast Asia transshipped through the region, dates and dried fruit, and any produce grown in heated glasshouses. The NFU has singled out tomatoes, cucumbers and peppers as the first categories likely to see price movement because their growers are the most exposed to natural gas prices [10]. The FAO has separately warned of a global food "catastrophe" if the strait disruption is prolonged [12].

How Self-Sufficient Is Britain, Really?

DEFRA's United Kingdom Food Security Digest 2025 puts the country's production-to-supply ratio at 65% for all food and 77% for indigenous-type food — that is, food the UK climate can grow [13]. The headline figure has held broadly steady for a decade but masks a lopsided dependence on imports for categories that the British climate cannot reliably produce.

Source: DEFRA United Kingdom Food Security Digest 2025

Data as of Dec 1, 2025CSV

The UK is close to self-sufficient in liquid milk, cereals and red meat, but imports about 80% of its fresh fruit and more than half of its fresh vegetables, overwhelmingly from the European Union and, for fresh produce specifically, from Spain (which supplies roughly 19% of British fruit and vegetable imports) and the Netherlands (about 11%), with South Africa accounting for around 5% [14][15]. The Netherlands is also the single largest country of origin for total UK food, feed and drink imports, at around 13% — a figure that reflects Rotterdam's role as a transshipment hub rather than Dutch farm output [14].

For the question of how long Britain could feed itself if import routes were severed, the honest answer is that no official stockpile figure is published. DEFRA has told select committees that the UK does not maintain strategic grain reserves of the kind held by China or the United States; it relies on commercial inventories in supermarket depots, which industry estimates typically hold only three to five days of fresh produce and two to three weeks of ambient goods. The Global Food Security programme and the National Preparedness Commission have both argued that this model is efficient in ordinary times but leaves almost no buffer against a simultaneous shock to imports and to domestic production inputs [16].

The Inflation Channel and Who Gets Hit First

The Food and Drink Federation, Britain's largest trade body for manufacturers, has raised its end-of-year food inflation forecast for 2026 from 3.2% before the strikes to 9%; some industry analysts put the high-end scenario at around 12% [17][18].

Source: Food and Drink Federation, ITV News, industry forecasts

Data as of Apr 1, 2026CSV

For context, UK annual consumer price inflation was running at 3.3% at the start of 2024 after peaking near 11% during the 2022–23 cost-of-living crisis [19]. A jump back towards double-digit food inflation would hit lower-income households disproportionately, because food accounts for a larger share of their weekly budget. The Trussell Trust, the UK's largest food bank network, distributed more than 2.6 million emergency food parcels in 2025 — a figure that was down 12% on 2024 but still roughly forty times the 60,000 parcels the charity handed out in 2010/11 [20]. Families with children received 62% of parcels in 2025 despite making up 42% of the population, and support for people aged 65 or over has more than tripled (a 247% rise) since 2019 [20].

Regionally, the North East, parts of the North West, the South Wales valleys and outer London boroughs consistently show the highest food-bank reliance and the highest share of households in food insecurity, according to Commons Library analysis [21]. Those are the communities where a 9% grocery-price shock would translate most quickly into skipped meals rather than postponed discretionary spending.

How the Plans Compare with COVID-19 and the Ukraine Grain Crisis

The Iran contingency work sits on top of two recent stress tests. In spring 2020, the UK relied on supermarkets' own resilience, relaxed competition law to let retailers coordinate on deliveries, and used temporary HGV driver concessions rather than formally invoking the Civil Contingencies Act. Russia's 2022 invasion of Ukraine, which disrupted global grain and sunflower-oil supplies and pushed fertiliser prices to records, produced a similar response: targeted state support for CF Industries' fertiliser plant at Billingham to keep CO2 flowing, rather than emergency legal powers [16].

Officials involved in Exercise Turnstone describe the current scenario as more acute than either precedent because it combines the fuel-and-fertiliser shock of 2022 with the CO2 fragility of 2021 and the logistics fragility of 2020, all triggered by a single chokepoint. That is also why lawyers have been asked to dust off the Civil Contingencies Act framework for the first time in the peacetime food context [1].

The Legal Machinery — and Its Limits

The Civil Contingencies Act 2004 defines an "emergency" broadly: any event threatening serious damage to human welfare, including disruption to the supply of food, water, energy or transport [22]. Part 2 of the Act allows ministers to make emergency regulations that can do almost anything an ordinary Act of Parliament could do — including requisitioning property, directing movement of goods, and suspending other statutes — but those regulations lapse after 30 days unless Parliament renews them and cannot amend the Human Rights Act, the Act itself, or create criminal offences punishable by more than three months' imprisonment [22][23].

The Act has never been used to declare a peacetime emergency; the government chose not to invoke it during COVID-19, legislating instead through the Coronavirus Act 2020, which was more narrowly drawn and subject to parliamentary review. If ministers did invoke Part 2 powers over food supply, they would face both statutory sunset clauses and the scrutiny of the Joint Committee on the National Security Strategy and the Commons Environment, Food and Rural Affairs Committee. Legal commentators have long argued that the sunset provisions are the most important single accountability mechanism, because they force ministers to keep going back to Parliament rather than letting emergency rules ossify [23].

The Case That Alarm Is Overblown

There is a credible argument for the opposite view. The UK imports almost none of its food directly through the Strait of Hormuz; the bulk comes overland from the EU or by container from the Americas, sub-Saharan Africa and East Asia on routes that do not touch the Gulf [14]. The exposure is indirect — through oil, gas and fertiliser prices, and through the subset of cooking oils, rice and dates that do transit the region — rather than through staples like bread, dairy or meat, where UK self-sufficiency is high [13].

Historically, global shipping has proved adept at rerouting. After the 2023–24 Houthi attacks in the Red Sea, container lines moved within weeks to the longer Cape of Good Hope route, adding cost and transit time but avoiding physical shortages on European shelves. Oil markets have a similar playbook: the Saudi East-West pipeline can move about 5 million barrels a day from the Gulf to the Red Sea, and the UAE's Habshan–Fujairah line bypasses Hormuz directly, though combined bypass capacity of 3.5 to 5.5 million barrels a day is well below normal Hormuz throughput of roughly 20 million [24][25]. UK North Sea production, together with Norwegian supply, also insulates Britain from the sharpest end of the crude shock relative to southern European economies [24].

Industry figures also point out that the CO2 supply chain has been fragile for years — the 2018 and 2021 shortages both prompted similar contingency work — and that the policy toolkit for dealing with it (subsidising fertiliser plants to keep running, importing liquid CO2 from Europe) is now well-rehearsed [4].

What Critics and Independent Experts Say

The NFU has used the moment to press a longer-standing argument: that UK food security is being undermined less by geopolitics than by domestic policy choices, including reforms to agricultural property relief, rising energy costs for glasshouse growers, and the steady loss of farmland to development [10][26]. NFU President Tom Bradshaw has warned that the Iran conflict could drive the biggest food-price spike since the Ukraine invasion and has pressed ministers on electricity standing charges for horticulture [10].

Independent food security researchers, including those at the Global Food Security programme and the National Preparedness Commission, have argued for years that the UK's civil food resilience framework has a gap: Local Resilience Forums, the statutory bodies set up under the 2004 Act, have no formal food-supply work stream, and central government guidance to them on food emergencies is thin [16]. Their critique is not that the current Turnstone exercise is alarmist, but that ad hoc contingency planning at the centre is a poor substitute for standing reserves, strategic stockpiles and designated food-resilience roles in local government.

Supermarket logistics chiefs, speaking anonymously to trade press, have been more sanguine, arguing that the British retail system absorbed the pandemic, Brexit border friction and the 2022 energy shock without empty shelves becoming a lasting feature, and that contingency planning is best understood as an insurance policy rather than a prediction [6][27].

The Bottom Line

The Iran war has not, at the time of writing, produced bare shelves in British supermarkets. What it has produced is a cascade of input-cost pressures — oil, diesel, fertiliser, natural gas, CO2 — that will filter into grocery prices over the coming months, and a set of government contingency plans that are unusually explicit about the legal powers ministers would need if the strait stays shut through the summer. Whether those plans represent prudent preparation or political signalling will depend on two variables neither Whitehall nor Downing Street controls: the duration of the conflict and the resilience of alternative shipping routes. For the households already stretched by a decade of rising food-bank use, the answer will matter less in the abstract than at the checkout.