devil's advocate : The non cynical reason for tax on petrol in the uk is that it's goal is to reduce consumption - to encourage people to own smaller cars, to use the train, to walk and so on.

The British government commited to reducing carbon dioxide emmisions in the uk by twenty percent as part of the Kyoto protocol so that we don't destroy the world.

This will require a reduction in petrol consumption. I have heard many people complain that petrol is expensive now, but I have not heard anyone say they haven't made a journey by car because of the cost of fuel. Does this mean the tax is a failiure because it isn't high enough ? Are there alternative ways of reducing fuel consumption ? Are there ways of reducing the political sensitivity of fuel tax ? (ring fencing fuel tax to pay for public transport infrastructure ?)