Energy regulator Ofgen said that more than four million people changed energy supplier last year, reducing their bills by around £150. By comparison, in France fewer than one in seven customers have changed supplier since 1998, and in Germany the proportion stands at one in ten.

Rising prices and inadequate levels of customer service appear to be the main triggers for looking at alternatives. The lesson for the suppliers is simple - give customers a good quality service at a competitive price and you can maintain market share; abuse that relationship at your peril.