The above building is thought to be the Cable Landing Station for the following cables:
Hermes South (OoS)
Pan European Crossing
The cables landing at Broadstairs are in the diagram below, with the remains of UK-Belgium5 seen as the red dotted line on the right of the diagram.
The out of service cables, Rembrandt2 and Hermes South land at the more northerly point, Pan European Crossing and Tangerine land at Dumpton Gap.
The yellow lines are power cables from offshore wind farms.