Beneath the Waves, Above the Law: Cables, Superpowers, and the Infrastructure of Mutual Destruction

Right now, as you read this, whether you're arguing with strangers on social media, transferring money to your landlord, streaming a television programme about the end of the world, or simply checking whether it will rain on Thursday, your data is almost certainly travelling through a cable thinner than a garden hose, sitting on the floor of an ocean. Not through a satellite. Not through the air. Through a wet, dark tube, under kilometres of water, running along terrain that would make a geologist weep with complicated feelings.

This is not a metaphor. Approximately 95 to 99 percent of all intercontinental internet traffic, along with international phone calls, financial transactions, classified government communications, and the coordinates that allow a drone to find something it shouldn't, travels through a network of roughly 600 submarine cables, collectively spanning over 1.4 million kilometres. The total economic value flowing through this infrastructure on any given day is, conservatively, in the trillions of dollars. The cables themselves, in many places, are no wider than a human wrist.

The remarkable thing is not that this system exists. It is that the average person has absolutely no idea it exists, is mildly astonished to learn of it, and then immediately returns to complaining about their Wi-Fi signal as though the two things are unrelated. They are not unrelated. They are, in fact, exactly related.

This is the story of how we built the nervous system of modern civilisation on the seafloor, handed it to a small number of corporations, ran it through a handful of geographic chokepoints, and then expressed surprise when things started going wrong.

Cornwall: Where the Future Came Ashore, Dripping

To understand where we are, one must first appreciate where we started, and where we started, with pleasing historical consistency, is in Cornwall.

In 1850, the first submarine telegraph cable was laid across the English Channel between Dover and Calais. It lasted precisely one day before a French fisherman, either confused or contemptuous of modernity, hauled it up, declared it a strange seaweed, and cut a section off to show his mates. The second attempt the following year proved more durable, and the age of undersea communication had, rather inauspiciously, begun.

Cornwall's involvement began in earnest in 1866 when the SS Great Eastern, Isambard Kingdom Brunel's magnificent, cursed, commercially disastrous behemoth of a ship, successfully completed the first permanent transatlantic telegraph cable, with the British terminus landing at Porthcurno, near Land's End. The choice was not romantic. It was logistical. Cornwall sticks into the Atlantic like a thumb, minimising the amount of cable required to cross to North America, and Porthcurno's sheltered beach offered a practical landing point. Sentiment rarely drove Victorian engineering decisions; profit margin did.

Porthcurno became, over the following decades, perhaps the most strategically important small beach in the world. By the early twentieth century, it was handling more international telegraph traffic than anywhere else on earth. During the Second World War, the cable station was buried underground, quite literally carved into the cliffs, because the British government understood, with commendable clarity, that destroying Porthcurno would do serious damage to the Empire's ability to communicate with itself. The Germans understood this too, which is why the RAF spent considerable effort ensuring they never got close.

The Telegraph Museum now sits at Porthcurno, a charmingly understated institution that contains some of the most consequential machinery in communications history. Tourists visit it after failing to find parking at the Minack Theatre. Britain, in its customary fashion, has placed one of the genuine wonders of technological heritage next to a car park and a cream tea establishment, and trusts that the interested will find their way.

Today, Porthcurno is still a cable landing station. The beach through which Victorian telegraph cables once ran now receives fibre optic lines carrying internet traffic. History, in Cornwall, does not so much repeat itself as quietly continue without making a fuss.

How the Things Actually Work: A Technical Digression That Is Less Boring Than You Fear

Modern submarine cables are engineering achievements that deserve considerably more admiration than they receive, largely because they are invisible and their success is indistinguishable from magic to the uninitiated.

A contemporary transoceanic cable is a layered structure of some elegance. At its centre sit optical fibres, typically between two and sixteen pairs, each one a strand of ultra-pure glass roughly the diameter of a human hair. Light pulses along these fibres at roughly two-thirds the speed of light in vacuum, carrying data encoded in those pulses at rates that currently reach several hundred terabits per second on a single cable. The physics involved is a field called wavelength-division multiplexing: different colours of light carry different data streams simultaneously, like several radio stations broadcasting through the same wire without interfering with each other. This is, if you pause to appreciate it, completely extraordinary, and yet we use it to argue about football.

Around the fibres sits a steel wire strength member, providing tensile support. Around that, aluminium water barrier. Around that, polycarbonate. Around that, copper, which carries electrical power from shore to the cable's repeaters, the amplifying stations built into the cable itself at intervals of approximately 50 to 150 kilometres, which boost the optical signal and prevent it degrading over thousands of kilometres of ocean. The whole assembly is then sheathed in polyethylene. In shallow water near shores, where anchors and fishing trawls and the general clumsiness of humanity pose risks, additional layers of armoured steel wire are added. In deep water, where the main hazard is nothing at all, the cable slims down considerably, to roughly the aforementioned garden-hose diameter.

Laying the cable is a task of extraordinary precision. Cable ships, a specialised class of vessel that exists solely for this purpose, move at walking pace across oceans, feeding cable off giant drums, keeping constant tension, charting the seafloor ahead with sonar, routing around underwater mountains, volcanoes, and abyssal plains. A single transoceanic cable project takes years to plan, 18 to 24 months to manufacture, and several months to lay. When something goes wrong mid-ocean, repair ships must locate a fault in a cable sitting at potentially 8,000 metres depth, using tools that would cause a neurosurgeon to nod with recognition, then grapple the cable to surface, repair it, and lower it back. This process takes weeks. It costs enormous amounts of money. It happens several hundred times a year, globally.

The cables also do not last forever. A typical operational life is 25 years before the technology inside becomes sufficiently obsolete that replacement is more economical than upgrade. Repeaters can fail. Earthquakes shift the seafloor and snap cables like shoelaces. Ships drag anchors over them. Sharks, for reasons that remain satisfyingly unclear, occasionally bite them. The ocean is, on balance, not an environment that has made peace with human infrastructure.

The Chokepoint Problem, or: We Really Did This to Ourselves

The Atlantic Ocean, vast, featureless from the surface, brutal from below, is actually the easy case. The chokepoints are where things become philosophically uncomfortable.

A chokepoint, in this context, is a geographic location through which a disproportionate quantity of the world's submarine cable traffic must pass because geography offers no convenient alternative. The Luzon Strait, between Taiwan and the Philippines, carries the bulk of cable traffic between East Asia and everywhere else. The Strait of Malacca, threading between Malaysia and Indonesia, is a narrow corridor through which an enormous proportion of cables connecting Europe, the Middle East, and Asia must travel. The Red Sea and its northern extension toward the Suez Canal represents perhaps the single most concentrated point of vulnerability for cables linking Europe to Asia and Africa. The waters around Egypt, specifically near Alexandria and along the Egyptian coast, carry so much of the world's internet traffic that a sufficiently motivated adversary with a boat and some patience could cause genuinely catastrophic disruption.

This is not a theoretical concern. In 2008, three cables in the Mediterranean were cut within days of each other, in separate incidents, affecting internet access across the Middle East, South Asia, and East Africa. In 2022 and 2023, several cables in the Red Sea experienced damage under circumstances that raised eyebrows. In January 2022, the Tonga volcanic eruption severed the single cable connecting the archipelago to the world, the country lost internet access entirely for five weeks. Five weeks. An entire nation, digitally severed from civilisation, because there was only one cable and the seafloor moved.

The problem is not merely that chokepoints exist. It is that they exist and we know they exist and we have, collectively, done very little about it. Redundant routing, building enough alternative paths that no single cut or cluster of cuts could cause catastrophic failure, is expensive. Routing cables through less convenient geography to avoid concentrating them in narrow straits is also expensive. And the people who build and maintain submarine cables are, as we shall shortly discuss, primarily motivated by profit rather than strategic resilience, which means they route cables where it is cheapest and most efficient, which is typically through the same chokepoints everyone else uses.

The result is that the infrastructure of global civilisation resembles, from a strategic standpoint, a circuit board with several traces that, if scratched, would make the whole thing stop working, and several of those traces run through waters adjacent to nations that are not our closest friends.

The Corporate Question: What Could Possibly Go Wrong?

In the early decades of submarine cables, the infrastructure was built and maintained largely by national governments and state-adjacent entities. This was expensive and inefficient. Then the 1990s arrived, bringing with them an ideological conviction that private enterprise should manage everything more important than traffic cones, and the submarine cable industry was reorganised accordingly.

Today, the global submarine cable network is dominated by a remarkably small number of companies. The ships capable of laying and repairing deep-sea cables number fewer than 60 worldwide, a figure that should cause one to pause. Of the entities that own and operate major transoceanic cables, a significant and growing proportion are either directly owned by, or are consortia substantially controlled by, four American technology companies: Google, Meta, Amazon, and Microsoft. These firms now own or co-own a substantial fraction of global undersea cable capacity, having determined, with the characteristic subtlety of corporations that have eaten the world's attention, that it was cheaper to build their own cables than to lease capacity from the traditional carriers.

This is a situation with several layers of concern, which one can peel back like an onion, finding under each layer another reason to feel vaguely uneasy.

The first layer: critical national and international infrastructure is now substantially owned by private corporations headquartered in one country, subject to that country's laws, and, should relations between that country and others deteriorate, theoretically subject to that country's government's instructions. No Western government has dwelt publicly on this at length. It would be impolite.

The second layer: these corporations are accountable to their shareholders. Shareholders want returns. Resilience, redundancy, and strategic depth do not generate returns in the short term. This is a tension that tends to resolve in one direction.

The third layer: the repair and maintenance capacity of the entire global undersea cable network depends on those fewer-than-60 specialised ships. If several of those ships are simultaneously occupied with conflicts, accidents, or simply booked for other work, the queue for repairs lengthens considerably. During the period when Tonga was disconnected, repair ships were occupied elsewhere. The world had to wait. Tonga had to wait. There is no strategic reserve of cable ships. There is no NATO rapid-response cable deployment force, though the argument for one has been made by people who follow this subject more closely than most defence planners apparently do.

The fourth layer, and perhaps the most quietly alarming: in recent years, there has been a series of cable cuts in the Baltic Sea, around the time of heightened tensions with Russia, that authorities have described, with diplomatic restraint, as likely not being entirely accidental. A Chinese container vessel was implicated in one incident. The cables that were cut connected Finland, Germany, Sweden, and Lithuania to the wider internet. Nobody has been formally charged. The ships involved sailed away. The cables were repaired, eventually. Everyone noted this with concern and then moved on.

The pattern, if you are the sort of person who looks for patterns, is not subtle.

Enter the Dragon, Dragging an Anchor

It would be remiss, it would, in fact, be a rather glaring omission, to discuss the concentration of submarine cable infrastructure without addressing the country that has spent the better part of two decades quietly building a parallel version of the whole system.

China's entry into the undersea cable industry began through Huawei Marine Networks, a subsidiary of the telecoms giant that became notorious for other reasons. Starting in the late 2000s, Huawei Marine penetrated markets in Africa and the Pacific by offering cable construction at prices its Western and Japanese rivals could not match, reportedly using heavily discounted, sometimes near-free projects especially to sell to developing economies. This was not, one suspects, pure philanthropy. In 2019, when Huawei was blacklisted by Washington, American pressure forced a restructuring: Huawei sold its majority stake to the Hengtong Group, a Chinese power and fibre-optic cable maker, which rebranded the unit as HMN Technologies. The Huawei name disappeared from the letterhead. The strategic intent, most analysts agreed, did not.

HMN Technologies has since become, by some measures, the world's fastest-growing subsea cable builder. In roughly the past decade, the firm completed over 100 projects laying tens of thousands of kilometres of undersea cable, a length that begins to strain the imagination and should certainly strain the credulity of anyone who believes this is a purely commercial enterprise. The firm's flagship project is the PEACE cable, Pakistan and East Africa Connecting Europe, which became fully operational in 2024, connecting Asia to East Africa and Europe while conspicuously bypassing India, a regional rival Beijing has little interest in routing the world's data through. The cable is owned by a subsidiary of the Hengtong Group. It is financed in part by Chinese state banks. It lands in Djibouti, where China also operates its only acknowledged overseas military base. The overlaps, one might charitably say, are suggestive.

The broader pattern is China's Digital Silk Road: a systematic effort to ensure that developing nations in Africa, South Asia, and the Pacific build their digital infrastructure using Chinese cables, Chinese equipment, and Chinese financing. China has encouraged countries to choose its cable networks with financial support and bids typically 20 to 30 percent cheaper than Western competitors, a discount made possible in part by state subsidy and in part by the kind of labour economics that Western firms prefer not to think about too directly. Washington has responded with countermeasures both financial and diplomatic, offering loans, training grants, and pointed warnings about intended sanctions against HMN Technologies, in an effort to steer contracts toward American firms. The result is a global infrastructure market that increasingly resembles two separate systems, laid along routes that reflect not engineering logic but geopolitical allegiance. The internet, which was designed to be borderless, is acquiring a physical topology that looks remarkably like a Cold War map.

The competition has produced some moments of almost comic obviousness. When the SEA-ME-WE 6 cable consortium, connecting Southeast Asia, the Middle East, and Western Europe, opened bids in 2021, HMN Technologies came in significantly cheaper than the American firm SubCom. Washington worked behind the scenes to change the equation, with a US interagency task force offering a combination of incentives and warnings of sanctions that eventually swung the contract away from the Chinese bidder. The Chinese consortium members, China Telecom, China Mobile, and China Unicom, promptly withdrew and announced they would fund their own separate cable on the same route. The internet now has two cables going to roughly the same places, built by competing superpowers, neither of which entirely trusts that the other's cable is simply carrying data.

Then there is the matter of what happens when diplomacy fails and someone's anchor becomes suspiciously active. Taiwan has long accused China of deliberately cutting its cables through grey-zone tactics, with China maintaining that any such cuts were maritime accidents, an explanation that began straining credulity somewhere around the eleventh incident. In early 2025, a Tanzania-flagged vessel controlled by a Chinese entity deliberately severed subsea cables near Keelung, disrupting Taiwan's external communications. Weeks later, a Togo-flagged ship with a Chinese crew that had cycled through multiple names and flag registries severed another of Taiwan's cables, and its captain was subsequently charged by Taiwanese prosecutors in the first such prosecution of its kind. Beijing described these incidents as common maritime accidents. Everyone noted, with the weariness of people who have heard this particular explanation rather too often, that the vessels involved had a pattern of switching names and flags specifically to frustrate maritime tracking, behaviour that is, as a rule, not associated with ordinary cargo shipping.

The tactical picture became considerably less ambiguous in early 2025, when China's state research apparatus published, in a peer-reviewed journal, details of a deep-sea cable-cutting device capable of severing armoured cables at depths of up to 4,000 metres, well beyond the operational depth of most existing subsea communication infrastructure, designed for integration with China's advanced submersibles. The device was presented as a civilian salvage tool. The timing of its disclosure, weeks after the Taiwan cable incidents, and the operational depth that places it well beyond any defensive measure currently deployed, were noted by security analysts with the kind of studied calm that military professionals adopt when they want to convey alarm without technically causing a diplomatic incident.

The Chinese government's position, apparently, is that it is simultaneously building the world's internet and retaining a well-publicised capability to cut it. This is either a posture of extraordinary strategic confidence or a form of communication so blunt it borders on the refreshing. Either way, it is not what the architects of the open global internet had in mind when they were routing fibre-optic cables past each other's coastlines and calling it progress.

What Is To Be Done, and Why We Probably Won't Do It

There are solutions to the vulnerabilities described above. They are known. They have been proposed. They are, in some cases, quite straightforwardly implementable given sufficient political will and budget.

More cables, through more diverse routes, would reduce the chokepoint problem. Increased strategic investment in repair capacity, perhaps through NATO, perhaps through allied nations collectively funding dedicated repair vessels, would improve resilience. Stronger regulatory oversight of cable ownership, to prevent further concentration in the hands of a few corporations and a few flags, would reduce the geopolitical risk. Better monitoring of cable routes, with faster detection of interference and a clearer international legal framework for responding to it, would make deliberate sabotage more costly and more likely to produce consequences.

The international legal framework, incidentally, is the 1884 Convention for the Protection of Submarine Telegraph Cables, supplemented by the 1982 United Nations Convention on the Law of the Sea, which between them provide a set of rules that were adequate for a world in which cables carried telegrams and the main threat was fishing boats, and which are somewhat underqualified for a world in which cables carry everything and the threats include state-sponsored hybrid warfare. The 1884 Convention is, one notes without enormous surprise, older than the aeroplane.

Progress is being made, in the way that progress is always being made on things that are not quite urgent enough to generate front-page coverage, which is to say, slowly, unevenly, and with the constant suspicion that it will be made somewhat faster after something goes badly wrong. Several NATO members have begun taking the issue more seriously since the Baltic incidents. The European Union has published strategy documents. The United Kingdom, home of Porthcurno and a nation whose global influence has historically depended rather substantially on its ability to control or at least influence undersea communications, has issued reviews and consultations and produced recommendations, as is its custom.

The cables, meanwhile, sit on the ocean floor, carrying your emails and your bank transfers and your streaming services and the communications of governments and the operational data of militaries, wrapped in glass and copper and polyethylene, repaired by a fleet of specialised ships that could fit in a middling commercial harbour, running through straits that the whole world's data has no choice but to transit. Two great powers are now building parallel versions of this system along competing routes, one of them having recently published the specifications of the tool it would use to destroy the other's. The 1884 Convention stands ready to help.

Cornwall still receives cables. The Victorians, at least, understood that the point where the wire meets the shore is where everything matters. Whether we have learned, in the century and a half since that first telegraph line came dripping up Porthcurno beach, to treat that fact with the seriousness it deserves, well. The answer is currently somewhere between "not quite" and "ask us again after the next incident."

Which, given current trends, should not be a long wait.

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