Danishch/ShutterstockThe UK government’s recent “Be Ready” campaign advises households to keep a three-day supply of food and drink in case of emergency. Sales of bottled water and tinned foods have soared, as households ready themselves for a powerful storm, a long power cut or a cyber-attack.
And preparing for three days of self-resilience seems like a sensible measure. But what happens on day four?
The hope would be that order is restored, with no further need for people to rely on their own supplies.
But what if the supply chains we rely on every day have not recovered in time? After all, it’s not as if they’re not vulnerable to attack.
Part of this vulnerability is down to companies using what we call a “just-in-time” strategy, where goods are produced or delivered just at the point that they are needed.
This means companies holding minimal stock levels, which reduces costs and waste. It can also involve using the same software across the supply chain to improve visibility and ensure accurate forecasting of demand.
And while all of these measures dramatically improve efficiency, one failure can hit several supply chains at once.
For example, in 2024, a cyber-attack on a supply-chain software company disrupted warehouse management systems and the supply of fresh produce for UK supermarkets. In 2025, a refrigerated logistics firm was targeted, causing widespread delays and cancellations of deliveries.
Also in 2025, a cyber-attack on M&S led to a five-day suspension of online sales and empty shelves in stores.
Read more:
How ‘digital twins’ could help prevent cyber-attacks on the food industry
Then in October 2026, hackers targeted French supermarkets, causing refrigeration units to overheat and spoil millions of euros worth of food. The UK’s food supply chain was affected by a similar attack on supermarkets across Europe at the start of November.
Just in time
This system, which seems to be so easily disrupted, was built for good and sensible reasons.
When businesses over order, or make inaccurate predictions about demand, food spoils. And research shows that poor coordination around production, logistics and sales leads to significant food wastage.
Sleek digital supply chains are designed to fix this problem. Forecasting software (which predicts who needs what and when) and automated ordering mean less food sits in a warehouse going off. That is a real gain, environmentally and economically.
Preppers’ delight.
fongbeerredhot/Shutterstock
The challenge is that these efficiency improvements can limit the capacity to absorb unforeseen disruption. When stores hold only a few days’ stock and every step depends on software, there is little to fall back on when something – a hacker, a flood or a war – cuts off supplies.
The UK government has been warned about this, with the National Audit Office saying that food supply chains have prioritised efficiency, keeping costs down for businesses and shoppers, but leaving them vulnerable to shocks.
So, does improving resilience mean giving up efficiency and returning to massive warehouse stockpiles?
Not necessarily.
After the Russia-Ukraine war disrupted wheat and sunflower oil supplies in 2022, we were part of a team which surveyed over 300 food manufacturers that relied on supplies coming from the region.
Waste not
The firms that coped best did two things. They worked hard to eliminate waste in their processes (by reusing and recycling materials, for example), and they quickly reorganised, finding alternative suppliers.
For supermarkets then, the lesson is to plan for disruption as seriously as they plan for efficiency. Two changes can be implemented in a short period.
The first is localisation, where sourcing more food from the UK will help shorten supply chains and reduce dependency on distant suppliers and long transport routes. The second is diversification, using more than one supplier for key products and more than one software or logistics provider.
In this way, a single failure cannot stop food from reaching the shelves. A chain with more than one route to the shelf is much harder to break.
Household supply chains matter too. Building up long-life supplies gradually, and using and replacing them in rotation, stops preparation from becoming waste.
Stocking up at home is a sensible first line of defence, and those who can follow the government’s advice should. But three days of tins cannot keep a country fed.
What happens on day four depends on decisions made long before any emergency: how much buffer stock the food system keeps, how many routes it has to the shelf, and how quickly firms can adapt. Resilience has to be built into the food system, not just people’s cupboards.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.