You need to define "London".
The Greater London Area (the area under the jurisdiction of mayor Boris and the Greater London Assembly) encompasses vast swathes of what were, prior to 1965, urban and rural districts. These areas now make up large chunks of the outer London boroughs. Much of this is farmland and open land interspersed with small villages, and criss-crossed by what are essentially country lanes. Many of these (almost certainly hundreds, if not thousands) have no lighting and are derestricted roads.