Thames Cable Tunnel
The Thames Cable Tunnel, also known as the Tilbury – Gravesend Cable Tunnel, is a tunnel carrying high-voltage electrical transmission lines beneath the lower River Thames between Tilbury and Gravesend. It remains the furthest tunnel downstream on the Thames.
Completed in 1970 at a cost of around £3 million by the Central Electricity Generating Board, the tunnel carries 400 kV transmission cables between substations at Tilbury and Kingsnorth as part of the National Grid. The tunnel is approximately deep, and was one of the first tunnels in the UK to be lined with pre-cast concrete segments rather than cast iron. A tunnel was chosen due to the high costs of building an overhead transmission line at this point in the river.
