The Labour leader will say that the new system will allow other providers into the market and help force costs down. He will cite a recent Ofgem report that found “four out of five consumers are at risk of paying more for their energy than they need to”. One Labour source said: “The shake-up would force traditional suppliers to bring down their cost and also mean new suppliers competing against them to bring down bills. Labour would also introduce a “simple tariffs” system where complicated and unregulated charges are not allowed. As called for by Which?, people would pay just a daily standing charge — similar to line rental on phone — and a set cost per unit of energy.”