As oil prices surged on Friday to a record of nearly $140 a barrel after a week that saw Asian governments abandon expensive fuel subsidies, airlines announce job cuts and politicians seek scapegoats among speculators, the question of whether demand would finally crack has been pushed to the fore.

America, for one, shows signs of finally starting to address its addiction to oil. This week General Motors, the biggest US carmaker, said it was considering ditching the division that makes its Hummer. That the most super-sized of all off-road vehicles is losing its appeal – in the year that the Smart, the key-ring-sized Swiss car made for two, landed in US showrooms after years of zipping around the narrow streets of Europe’s capitals – has been duly noted by economists tracking oil demand at the International Energy Agency (IEA) in Paris.