Neither. Its a price increase in oil as the oil markets are going a bit crazy with all the talk of war. Theres nowt oil coming out of Iraq in global terms, but if the Saudis get scared and cut production...
Its all hyopthetical, but traders buy future supplies of oil. If they think that the price for oil in a few months time will be higher, they buy now to sell later at a profit. In fact, many completely unrealted companies have staff especially to buy and sell oil as its so profitable if done right - someone like M&S will make more by oil speculating than from many store lines.
The tax on fuel is a proportinate tax - i.e. a percentage one. So if oil cost 10p and its 10% tax, then what we pay is 11p. But if the oil rises to 11p, the price rises to 12.1p as 10% of 11p is 1.1p. The former tory govt introduced a fuel tax escalator - whereby tax on fuel rose every year by law. Labour scrapped it after the fuel protests of 2000.