[Symbiote]

20kV is not very much, the one in the picture is probably 275 or 400kV.

The pylon shown is the end one — the wires on the left side go down to the ground. It's probably on the edge of a city somewhere, within British cities electricity distribution is buried.

[ptaipale]

Yes, 20 kV is not much, but also 400 kV can be underground. What I meant is that even with such low voltage as 20 kV and even in countryside it may be worth it to bury the cable.