FEEDER

There's a blank-faced building behind security fences on the Cornish coast, which is where many trans-Atlantic fibre-optic cables reach the shore after thousands of miles in the depths of the ocean. From there, a never-ending torrent of data spews out into the UK's networks, of video and sound and text, all of human life and commerce rising up out of the ocean or diving back down the other way.
In an air-conditioned room in a permanently locked corner of the building, a set of servers hum contentedly as they siphon off every last byte to the supercomputers of GCHQ, which pick at it by keyword or expert learning algorithm, drawing out what the state wants to know.
Although highly classified, this is now a fairly open secret, and many are in the know.
What is less well known is that a thousand feet below the earth, buried deep in the rock, a living thing lies, a thing as big as a blue whale, twisting and turning in pleasure as it feeds off the representation of human lives that pass through above, arching in ecstacy as it feels the anger, the hate, the betrayal, the disappointment, the horror, the pain, the bile, the fear. it feeds off it, and it grows.
Only six people know that this thing exists. Five of them work, in one way or another, for governments. The other is dishevelled man with an unkempt beard who rents a small caravan in a run-down park nearby, and spends his days beachcombing, while he works out how he is going to kill it.