t was as though a ghostly hand had switched the settings on supermarket freezers across Europe from "freeze" to "defrost". From Finland to Ireland, they suddenly began heating up, many reaching 50C and food worth millions of euros had to be thrown away. But no actual hand was needed to cause the meltdown. This was a cyber-attack, or rather a chain of attacks. Like pretty much everything else in 2026, supermarket freezers are digitally enabled. That makes them smarter and more efficient, but like everything else that is connected to the internet, it also makes them more vulnerable.

Russian hacktivists claimed they were behind some of the supermarket sabotage, but no one knows for sure. It could also be Iran, Iranian proxies, North Korea – or unaffiliated bedroom hackers. When Transport for London suffered a devastating hack two years ago, the culprits turned out to be two British teenagers. Governments regularly warn retailers and other companies about cyber-attacks and even provide cyber-defence training to businesses. The lessons of costly ransomware and cyber-attacks also mean many big organisations and retailers have become much better at keeping their payments and logistics systems safe.

But freezers present a new vulnerability. In Sweden, for example, some of the stores that were attacked this week hadn't connected their freezers to national retailers' systems, which have centralised protection. Now they've learned their lesson the hard way.

Hybrid warfare – or, to use the defence term, greyzone aggression – refers to an array of hostile acts by a country's adversaries that fall short of full-on military conflict. Cyber-hackers also this week attempted to meddle with fridges at French blood banks, while hoax bomb threats forced commercial airliners across Europe to divert, make emergency landings or require fighter jet escort to safety.

This comes after at least two years of sporadic Kremlin-suspected arson attacks on factories, explosives-laden drones flown into airports and drone incursions into countries' airspace. There is constant GPS interference in the skies around the Baltic Sea, highly suspicious damage to subsea cables and pipelines, disinformation spread by bot farms and repeated acts of cyber-aggression.

Saboteurs and hackers usually have two aims: the first is to disrupt, but they also want to psychologically destabilise the target societies by spreading fear. It is fortunate then that the aviation hoaxes and freezer incidents coincide with a renewed conversation across Europe about resilience. It is as if the hackers wanted to showcase the need for preparedness projects such as the UK government's new Be Ready campaign, which launched last month.

The British campaign, which instructs people on such things as stockpiling for emergencies whether caused by climate change or state-sponsored terrorism, had been in the works for months. Ministers hesitated however, fearing that citizens would respond with cynicism or ridicule, or just wouldn't follow the advice.

Such campaigns are commonplace elsewhere. Earthquake zones such as Tokyo and San Francisco have had them for decades. "Make a Plan. Gather Supplies. Get Connected. Get Trained," are the San Francisco city government's pillars of instruction.

The newest version of Sweden's official booklet In Case of Crisis or War, distributed to every home since 2018, is even more comprehensive, with clear language about everything from civil defence duties, how to volunteer (give blood or team up with neighbours for mutual support), to what items always to have at home, and how to find out if a crisis is real or a fake warning by bots.

For several years, I have been calling on the UK to follow Sweden's lead and send a similar instruction leaflet to UK households, only to be told by officials that doing so would cause too much panic and frighten people. A House of Lords committee heard from the chair of the UK National Preparedness Commission in March that "the bulk of the UK population is blissfully unaware" of some of the risks they face.

It turns out that British people are less cynical than their leaders had assumed. Perhaps a few minds were also changed by Covid-19, which dramatically illustrated how vulnerable globalised and open societies are to all manner of threats.

Either way, within a week of the Be Ready campaign launching, the retailer Robert Dyas reported that weekly sales of radios had shot up by 160%. Maplin reported that sales of radios had nearly doubled and sales of power banks had more than doubled, while torch sales had soared to nearly four times the usual figure.

The puddles of defrosted ice in the supermarket aisles and stress for air travellers this week show that we need to be prepared for a very wide range of threats including power and water outages. We have already seen what happens to our complex food supply chains when global shipping lanes are suddenly disrupted. Iran's obstruction of the strait of Hormuz following US airstrikes has given us painful food inflation and costly global oil and fertiliser shortages.

But what if the ships importing the food we eat can no longer make it to our ports? No industrialised nation grows all the food it consumes. What if the internet goes down? It's not impossible. Even companies with the best cyber defence could fall victim to sabotage of the subsea data cables that transmit nearly all our connectivity.

This week has been a nasty preview of what could happen in future with alarming regularity. Severe disruption will come our way so simply hoping for the best is not an option. The good news is that by accepting that we need to prepare, and demonstrating that we remain strong in times of crisis, we can signal to Vladimir Putin and other rogue actors that disrupting our services is unwelcome, but ultimately it is futile.