Hezbollah aren't the only ones who should learn lessons from Israel's exploding pagers

At 3.30pm on Tuesday, the world entered a new era: one in which warfare will be waged against individuals by means of targeting personal devices. The exploding pagers, walkie-talkies and other devices planted by Israel have not just killed a couple of dozen Hezbollah fighters and injured thousands more (together, regrettably, with innocent bystanders).

They have also seriously impeded the ability of Hezbollah to communicate with its fighters. The terror organisation had already ditched mobile phones for fear that they could allow Israel to track the location of Hezbollah operatives.

Pagers, which most of us consider now to be an obsolete form of technology, were supposed to make communication safer. Now, the group will be reduced to using flags and messengers to pass instructions between members.

Much as we might like to, no one in Britain can stand aside from this dramatic escalation in tactics used by Israel against its enemies. Now we have been shown what is possible, we have to face up to the serious implications. We, too, are highly vulnerable to warfare conducted by novel means involving electronic devices.

It's astonishing to think that, until four years ago, the UK government was intending to allow our 5G mobile broadband network to be based around Chinese-made kit. We are not at war with China, of course, and hopefully we never will be. But as a militant dictatorship it is clearly a potentially hostile nation. Would we really want to grant it the ability to intercept and interfere with our communications network?

It took warnings from the US before our own government changed its mind and decided that, after all, perhaps the cost and speed of deployment of new technology should take second place to considerations of national security. The Americans said they would refuse to share military intelligence with us if we continued to build a communications network based on Chinese-made kit.

Such equipment is now steadily being removed from our broadband network. Two years ago, the then-Conservative government also banned new Chinese-made CCTV cameras from sensitive locations - although many older ones remain in place.

It is not hard to imagine how a hostile power could use electronic equipment to target us. As this week's pager explosions show, it is possible to install military grade-explosives within small personal devices without the buyer or the user having the slightest idea what has been done. But it is even more difficult to detect when software has been installed in a device which would allow it to be controlled remotely.

This is different from trying to hack computers externally - which itself is hard enough to defend against, as past attacks on the NHS computer system and others have shown. If you manufacture an electronic device from scratch, you really can programme it to do whatever you want it to do - and no user could tell what you had done simply by taking it apart.

Indeed, we could end up with a situation in which most of the country's mobile phones suddenly ceased to work, or were programmed to send us propaganda or fake news.

We like to think of our cars as being autonomous, yet increasingly they are being connected to the internet, especially electric ones. They could all be brought to a grinding halt at the flick of a switch.

The whole idea of 5G is to connect many more everyday appliances to the internet. Tempting though it might be, say, to tap into an app and be able to turn on our central heating half-an-hour before we get home, such technology brings with it risks.

A hostile power could create havoc by switching off our central heating during a cold spell, or by turning off our fridges to spoil vast amounts of food.

The only way we can hope to defend against cyber warfare is by keeping a very close grip on supply chains of electronic goods, and to ensure that we are not all using devices that are manufactured by a common source. It was almost certainly Hezbollah's decision to make a bulk order of pagers at a time when few people use the devices any more that alerted Israeli intelligence to the opportunity to booby-trap the devices.

Above all, this week's events provide a strong argument for bringing much more manufacturing back home. Over the past few decades we have become far too dependent on electronics and other devices manufactured in South Asia.

Obviously, globalisation provides huge opportunities to increase the efficiency of industrial production and so make us richer. When countries are free to concentrate on what they do best, global prices for things such as computers, smartphones and other goods tend to fall.

Globalisation is why until recently we have enjoyed three decades of low inflation.

Yet we also have to recognise that it brings risks. While Britain hasn't itself been targeted this week, the events in Lebanon should wake us all up to the grave new era of cyber warfare.