An oil price above $125 a barrel, however, and speculation that the price could hit $200 are reminders that we have become ever more dependent on the black stuff.

because truck drivers and commuters cannot easily stop travelling, even a small deficit in supply can cause large moves in the oil price.

Expensive oil has economic effects.

Middle Eastern producers can buy more German cars, French clothes and US Treasury bonds in exchange for each barrel. Importers must buy less of everything else in order to keep up their consumption of oil.

Higher oil prices can, but need not necessarily, cause sustained inflation. A rise in the price of oil should be offset by falls in the prices of other goods for which there is now less demand.

Oil-intensive capital equipment may have to be scrapped: the useful life of all of sports utility vehicles, farm equipment and gas-fired power stations, for example, may be shortened.

when combined with higher food prices, it will mean more poverty.