Most households paying £250 a year too much for energy

Shadow Energy Secretary Caroline Flint. MP for Don Valley, said Department for Energy and Climate Change (DECC) figures showed that 75 per cent of households were on their supplier’s standard variable tariff.

The standard variable tariff was on average more than £180 a year more expensive than the cheapest tariff, with some customers paying nearly £250 a year more, Ms Flint said.

She said Mr Cameron had promised 17 times in the House of Commons to make energy suppliers automatically put all customers on the lowest tariff.

She said: “More than two years after David Cameron promised to make energy companies put all customers on the lowest tariff, millions of households are still being routinely overcharged by hundreds of pounds every single year.

“That’s why the next Labour government will freeze energy prices until 2017, so that bills can fall but not rise, give the regulator the power to force energy suppliers to cut their prices and end overcharging once and for all.”

Last month the Competition and Markets Authority (CMA) released early findings of an inquiry into the sector that found the Big Six were overcharging millions of loyal customers by up to £234 a year.

Its findings showed 95 per cent of the UK’s 19 million dual fuel customers – those people who take gas and electricity from the same company – could have saved between £158 and £234 by switching tariff or supplier.

The CMA found the Big Six had consistently charged higher prices for standard variable tariffs than for other deals such as fixed tariffs.

The chief executive of the energy industry’s trade body Energy UK, Lawrence Slade, said: “Standard variable tariffs are just that, the standard price a company is offering energy to customers. Part of the cost of energy is an assurance that the gas and electricity has been bought months in advance, making sure that energy will be available to customers when it is needed.”

Mr Slade added: “If a customer thinks they might be able to save some money by switching tariff or company, they should log on to a comparison site or call their supplier.”