Britain is quietly preparing for disruption to supermarket shelves this summer as fears grow over the impact of the Iran conflict on global supply chains.

Government officials have been running internal emergency scenarios looking at what happens if the Strait of Hormuz remains closed and tensions drag on. One of the biggest concerns is a collapse in carbon dioxide supplies which are critical to the UK food system.

CO2 is used across the industry from keeping packaged food fresh to the slaughter of pigs and poultry. Without it large parts of the food chain begin to slow down very quickly.

Under the government’s worst case planning UK CO2 levels could fall to just 18 percent of normal supply. That would not mean empty shelves but it would mean less choice for shoppers and visible disruption across supermarkets.

Products like chicken pork salad and baked goods are among the most exposed. Farming and hospitality are expected to be hit first with knock on effects across the wider economy.

There are also growing fears of alcohol shortages during the World Cup this summer as falling CO2 supplies could leave breweries struggling to keep up with demand.

The risks go beyond food. CO2 is essential for producing dry ice which is used to transport blood supplies organs and vaccines. Officials have warned that shortages at that level could pose a direct risk to life.

The government has already begun drawing up emergency measures to deal with the situation. Plans include forcing factories to switch production towards CO2 even if it means shutting down other manufacturing lines.

Ministers are also considering relaxing competition laws to prioritise limited supplies for critical sectors like healthcare. In more extreme scenarios emergency powers could be used to take direct control of parts of the supply chain.

Companies could be compensated for halting normal production with the cost expected to run into tens of millions.

As a short term fix a major bioethanol plant in Teesside has already been restarted to boost domestic CO2 output.

Officials stress that these scenarios are not predictions but contingency planning. However similar shortages were seen in 2022 when rising energy costs forced key plants to cut production.

Keir Starmer has said the priority is reducing tensions and reopening the Strait of Hormuz warning that global supply routes depend on it.

Talks involving more than 40 countries are ongoing but uncertainty remains over whether the current ceasefire between the United States and Iran will hold.

A government spokesperson said the UK is continuing to work with industry to protect critical supplies and that worst case scenarios are standard planning not forecasts of what will happen.