Fawley Tunnel

A connection to the 400 kV sub-station at Lovedean some 10 miles to the north east was the ideal location.

[2] Firstly, to route overhead lines west from Fawley then around Millbrook to the north of Southampton.

The third option was to construct a two-mile underground tunnel beneath Southampton Water.

[4] The tunnel was excavated under a pressure of 35 psi to prevent water ingress and is lined with cast iron segments.

Cables were laid in triangular configuration in an open duct through which water flowed under gravity from one end of the tunnel to the other.