The energy market is not working properly and the government “will not hesitate to act” to ensure more is done to help retail consumers, Ed Miliband, the new energy secretary, said on Thursday.

Gordon Brown underlined the government’s determination to be seen to be acting on rising fuel costs – a core issue for many Labour MPs. The prime minister turned up the pressure on petrol retailers, pointing out that while some supermarkets were selling fuel at less than £1 ($1.7) a litre, it was selling at £1.20 in some areas.