Subsea telecommunications cables

Physical cables beneath the sea carry international communications. Their capacity, landing points and connections on land matter as much as their number; damage to one cable does not automatically disconnect a country.

Subsea telecommunications cables link networks across seas and oceans. Their land connections and the data centres they serve are part of the same working system. The familiar idea of information travelling through the cloud still depends on physical infrastructure.

A September 2025 UK parliamentary report estimated that two cables landing at Bude accounted for about 75% of the UK’s direct transatlantic capacity. That figure describes capacity on particular international routes, not 75% of all British internet use.

The report also described alternative routes through Europe and established repair arrangements. The practical question is how much usable spare capacity is available when damage occurs, and whether traffic can reach it. Several damaged routes, power failures or inaccessible land connections can complicate recovery. Such possibilities are resilience questions, not evidence that a specific attack is imminent.