Wake-up calls do not come any more urgent than this. As the US authorities investigate the cyber hack that has invaded America’s most sensitive agencies – with possible intrusion into Britain’s security too – it is rapidly becoming evident that the seriousness of the situation is greater than was at first believed, its gravity almost impossible to exaggerate.

Organisations that have been penetrated include US Homeland Security, the State Department, the US Treasury and the Pentagon. Analysts believe the attacks were launched months ago, meaning that the hackers have had access to America’s most sensitive secrets since at least last summer. FireEye, the specialist IT security firm, has admitted it has itself been hacked. Target computers were allegedly infected via SolarWinds Orion, a network monitoring tool for Microsoft Windows.

This disaster is the cyber equivalent of Covid-19, with similarly damaging implications. Cyber chatter points the finger at Russia’s APT29 (“advanced persistent threat”) Cozy Bear team as the perpetrators, but there is no solid evidence so far. Whatever the source of the attack, it has left the world’s leading high-tech superpower – the home of Silicon Valley – looking vulnerable in the face of cyber warfare.

Britain is at risk too. The Ministry of Defence has ordered an urgent review of all systems to discover what information has been compromised. Microsoft has warned that UK customers were among those who installed SolarWinds software. The damage inflicted on the technological giant America can hardly encourage us to feel safe. The recent defence spending review confirmed the creation of a National Cyber Force, combining the resources of GCHQ, the Ministry of Defence, the Secret Intelligence Service and the Defence Science and Technology Laboratory.

In fact, Britain has been engaged in cyber warfare for years, against Islamic State for instance, and this formalisation of that arm of our defences simply reflects the growing significance of this form of warfare. The reality is that cyber war is the future of conflict. War is a continuing phenomenon, unlikely ever to disappear from human experience, whose historical development demonstrates very identifiable watersheds. These, broadly, could be itemised as the discovery of gunpowder, the invention of aircraft and the creation of atomic weapons.

To that chronicle there must now be added cyber warfare, a development as historic as any of the preceding watersheds. Like the emergence of aerial warfare and nuclear weapons, it has the unfortunate consequence of putting civilians in the front line, with hospital trusts a main target of hackers, as in an attack attributed to North Korea in 2017 which resulted in the cancellation by UK trusts of 19,000 operations and hospital appointments. That is potentially fatal for some patients, as the legitimate delays imposed by the Covid-19 pandemic have demonstrated statistically.

Another sinister aspect of cyber warfare is that it is, in the worst sense, egalitarian: it costs little and its victories can be enormous, as a stunned America is currently discovering. As a prescient article in Forbes magazine last January, warning that 2020 would see an explosion of cyber warfare, asked: “why spend ten or fifteen billion dollars on an aircraft carrier when you can disable it digitally?”

North Korea recognised the potential for cheap cyber aggression to level the playing field between impoverished rogue states and superpowers a long time ago. In tandem with the drone, cyber war hugely reduces the advantage previously enjoyed by the conventional forces of major powers. The Nato powers need to address ways of eliminating that new imbalance.

There is no reason why they should not quickly succeed. Despite its recent setback, the United States’ cyber warriors are regarded as the best in the world. Britain’s new National Cyber Force is being given the resources to achieve its mission, in the words of Jeremy Fleming, the director of GCHQ, “to transform the UK’s ability to contest adversaries in cyber space, to protect the country, its people and our way of life”. This is a war that we must win.