The commodities slump muddies an already complex picture

Just as central banks have been getting out their big guns to fight levels of inflation that had caught them all unawares, global financial markets have sprung another surprise. Rate-setters had been criticised for neglecting accelerating prices in favour of support for growth. Now, it seems possible that they may find themselves accused of the opposite.

Over the past few weeks, many of the commodity prices that were at the centre of…