The rise has been sudden and dramatic. Early this year a lone trader in New York pushed the price of oil above $100 a barrel for the first time, taking the world into a new era.

It did not last, sparking suggestions that the trader had ensured his place in history but very little else. Then, a few weeks ago, the upward march began again. Last weekend, with oil markets twitchy about the closure of the Grangemouth refinery in Scotland and a dispute affecting Nigerian oil output, prices came within a whisker of $120 a barrel. ... Read full article