The bigger issue is that the price of fuel has risen over the past year or so because the price of oil has increased, and not because of changes to fuel duty. Reducing fuel duty by a few pence would be just a short term sticking plaster. Successive governments have stuck their head in the sand about peak oil production (the point at which the rate of oil production cannot be increased), which is a far more significant factor in price rises. The answer is to make the country less oil dependent and more efficient.
For many drivers, the price of fuel evidently isn't affecting them... There are excessive numbers of inefficient 4x4 type vehicles on the road with appalling fuel consumption. For a lot (not all) of drivers a more efficient car is an option for them and could easily yield an extra 20 - 30 mpg. If that isn't an option, driving more efficiently is - you still see a lot of people accelerating ridiculously, racing to the back of queues to slam their brakes on, breaking the speed limit, driving round with roof bars/boxes on they're not using and so on. I don't doubt those same drivers are probably complaining about the price of fuel....