“What do you mean, nobody’s fault? It has to be somebody’s fault!” Politicians’ reactions to oil prices over $145 a barrel and diesel over £1.32 a litre are reminscent of the ferocious Lucy in the Peanuts cartoon strip.

As the cost of oil has soared, everyone has been looking for someone else to blame. The MPs on the Treasury select committee on Thursday fixed on the mysterious and allegedly powerful role of “speculation”, echoing Harold Wilson’s famous evocation of the “gnomes of Zurich”.