It is worth remembering that oil is the life blood of the world economy. Without oil, people starve. In the 1970s, when Sheik Yamani led Opec to put in a massive price rise, world recession took place. The oil producers, much to their surprise, suffered as much as anyone. The World Bank and others persuaded them that recycling their new found wealth was key to their own prosperity. Hence they are now a key driver of investment throughout the world. Oil will, of course, become less used over the next decades and the current investment programmes will bear fruit and replace oil revenues.