Brits are being braced for a summer of shortages with warnings that chicken and pork are among a swathe of products at risk from the Iran war.
A 'reasonable worst case' scenario drawn up by the Government suggested that disruption to carbon dioxide supplies from the Middle East could have major impacts.
In a war game staged by ministers, gas needed to be prioritised for healthcare - where it is crucial for kit such as MRI machines - and civil nuclear power.
But that could affect slaughterhouses, with most pigs and chickens killed using the gas. Breweries and soft drinks manufacturing could also be hit.
The possibility will add to fears about looming issues with diesel, jet fuel and fertiliser as the turmoil continues from Donald Trump's war on Iran.
Officials from No10, the Ministry of Defence and the Treasury were among those involved in 'Exercise Turnstone', according to The Times.
Although overall food shortages were seen as unlikely in the Government exercise, there were concerns that shoppers would see less choice (file picture of supermarket)
Keir Starmer is said to have been deeply involved in the contingency planning
It considered a situation where the Strait of Hormuz still had not reopened by June, and there was no permanent ceasefire.
Factories could be ordered to focus all their efforts on producing CO2, and legally compelled if necessary.
Although overall food shortages were seen as unlikely, there were reportedly concerns that shoppers would see less choice.
The war-gaming session was apparently attended by officials from the Food Standards Agency, as well as the health, business, environment and energy departments.
The 'reasonable worst-case' scenario saw supplies of CO2 drop to 18 per cent of normal levels, with a key UK plant suffering a mechanical error.
It also proposed a situation where high natural gas costs squeezed ammonia and fertiliser production across Europe. Those industries generate CO2 as a by-product.
Business Secretary Peter Kyle attempted to cool concerns as he toured broadcast studios this morning.
Asked about the availability of CO2 in the country, he told Sky News: 'At this moment, this is not a concern for the economy.'
He added: 'If any of these things change, I will be up front with the public about it in advance so that we can prepare.
'But right now, people should go on as they are, enjoying beer, enjoying their meats, enjoying all the salads.
'But also there are critical uses for CO2: MRI scanning, for example, water purification; it's involved in our nuclear industry, our civil nuclear power industry, some defensive uses for it as well.'
Mr Kyle refused to comment on specifics of the leak, but told Times Radio the public should be 'reassured that we are doing this kind of planning, and we are doing this kind of scenario planning'.
The possibility will add to fears about looming issues with diesel, jet fuel and fertiliser as the turmoil continues from Donald Trump's war on Iran
'I can tell you, because I'm in these meetings, the Prime Minister has been there since the very start, and he is going through personally and driving deep dives into lots of areas of resilience throughout our economy,' he said.
Mr Kyle pointed to his own decision near the start of the conflict to reverse the mothballing of the Ensus bio-ethanol plant in Teesside to secure supplies of carbon dioxide.
He added: 'People should be reassured that we are doing this kind of action behind the scenes to keep resilience in our economy, so that when the full extent of what may or may not emerge, because this situation is still unfolding in the Middle East, you have a Government that is acting with creativity and boldness.'
Meanwhile, Rachel Reeves has expanded plans to cut electricity bills for thousands of UK manufacturing firms as she continues talks in Washington DC focused on the economic fallout from the Iran conflict.
In a bid to help businesses hit by rising costs, a plan announced last summer to cut electricity bills by up to 25 per cent for more than 7,000 UK businesses will be expanded to cover 10,000 firms.
The British Industrial Competitiveness Scheme (BICS) will cut costs by up to £40 per megawatt-hour from 2027 by exempting businesses from certain extra charges that currently support green energy and back-up power supply systems.
An additional one-off payment in 2027 will be given to an extra 3,000 businesses, including companies in the automotive, aerospace, steel and pharmaceuticals sectors.
The Chancellor, who is in the US for the International Monetary Fund (IMF) spring meetings, said the plan will help UK businesses compete and create jobs despite the uncertain economic backdrop.
During her trip, she has stepped up criticism of US-Israeli military action in Iran, saying war was a 'mistake' and has not made the world a safer place.
Her comments came as she was due to meet US treasury secretary Scott Bessent, who has referred to the impact of the war as 'short-term volatility for long-term gain' which he said would prevent Tehran developing a nuclear weapon.