A price-stabilising fuel duty

Concerns about fuel taxes and road duties are growing.  At the time of the 2000 protests, I had a number of articles published arguing for a "price-stabilising fuel duty".  The purported reason for taxes on fuel being so high is environmental (though in fact on most standard estimates such duties exceed the costs of the associated environmental externalities).  The idea was supposed to be to achieve a price that gives appropriate signals about switching away from carbon-based fuels towards alternative energies.  My contention was that if the government is to fix the price, it might as well do so competently, achieving the price (or around the price) that is its target.  Recent events have presumably driven fuel prices well above the target price (otherwise the logic of the argument would be that fuel duties should previously have been much higher).  Under the scheme I favoured, fuel duty would be automatically inversely related to oil prices, rising as oil prices fall and falling as oil prices rise.  Perhaps it's time to consider this again?