Late last month, the undersea cable that supplies internet to the Shetland Islands was cut in two places. Such incidents are usually accidents, but the presence of a Russian underwater research ship, and the recent trio of underwater explosions that severed the Nordstream gas pipeline, make Moscow sabotage far more plausible.

Ever since the collapse of the Soviet Union, the west has been able to luxuriate in security through technical superiority. Nato comprehensively outcompeted the Warsaw Pact. We excelled in aerospace technology and built superior submarines. The digital revolution, largely driven from Silicon Valley, further widened the gulf. The Five Eyes intelligence partnership, with eyes and ears in space, reigns supreme. But space and cyber space are increasingly being democratised and can now be accessed at low cost. Hostile powers have calculated that this is where they can attack Nato countries to great effect.

Few are aware just how dependent we are on a limited number of fibre-optic cables that form the internet’s spine and electronically link our continents and islands. Currently 95 per cent of international internet traffic is transmitted by undersea cables; satellites, in comparison, convey very little. There are still only about 200 cables around the world, each the size of a large hosepipe and capable of data transfers at about 200 terabytes per second. These cables — which carry an estimated $10tn worth of financial transactions every day — come together at 10 or so international chokepoints, which are particularly vulnerable.