That rumbling sound is a massive shift in consumer behaviour. At a time when retailers are searching for words to describe the violence of the downturn in their businesses, Best Buy chief executive Brad Anderson reached for a geological comparison. Warning on Wednesday that like-for-like sales for the four months to February could be down 15 per cent on the previous year, the largest electronic retailer in the US reported a “seismic” change in spending patterns.

It is not alone. Intel threw out a profit warning of its own on Wednesday night. The world’s largest maker of semiconductor chips cut forecasts for fourth quarter revenues and gross margins by about a 10th, citing weaker-than-expected sales across all regions and geographies.