Of all energy policy, anything affecting how much people pay to drive ranks among the most politically sensitive. Just ask Steven Chu, who admitted raising US petrol taxes was not politically feasible, despite his belief that such a move would reduce carbon emissions and energy dependency.

Despite this, politicians in both the UK and the US spoke have spoken this week about different approaches to raising revenue for roads and changing driving behaviours. While some innovative ideas were suggested, it also serves to underline just how what a difficult area this is. Never mind getting popular support for changing or reducing vehicle use; even getting drivers to pay for roads is difficult enough.

The BBC was this morning led with the MPs’ cross-party transport committee, which said the whole concept of environmental taxes had been “damaged” by the handling of a proposed rise in vehicle excise for the highest polluting cars.