According to price comparison website MoneySuperMarket, 3.1 million British Gas customers will be hit by a 12.5 per cent increase in electricity prices on Friday.
Increases will affect those on a Standard Variable Tariff and the website estimates that the changes will collectively cost households £235m per year.
Earlier this week Energy UK, the trade association for the UK energy industry, said that nearly half a million customers switched their supplier in August 2017. But MoneySuperMarket estimates that around 70 per cent of UK households are still on expensive SVTs from the Big Six providers – British Gas, EDF Energy, nPower, E.On, Scottish Power and SSE.
The website said that the average annual cost of an SVT with one of those six providers is now £1,151 but the average cost of the top twenty tariffs available in the market is £855.
“During 2017 all of the Big Six energy suppliers have increased their prices – so it’s no wonder households are getting frustrated,” said Stephen Murray, an energy expert at MoneySuperMarket.
“As we approach winter, consumers need to take matters into their own hands and switch their energy supplier immediately.”
The company, which is owned by Centrica, announced its latest round of price rises in August, prompting calls for greater regulation amid fears that a fresh round of increases could hit households over the winter.
Business and Energy Secretary Greg Clark wrote to regulator Ofgem in June asking what action it intended to take to safeguard customers on the poorest value tariffs and the future of the standard variable tariff.
Since then, Ofgem has committed to taking action, saying that it would consult with consumer experts to develop ways of safeguarding tariffs.
At the end of August, Theresa May dropped her campaign pledge to cap energy bills of 14 million households, prompting outcry from campaign groups.
“Consumers are sick of the endless debate about energy prices and just want to see action,” Alex Neill, managing director of home products and services at Which? said this week.
"It's down to the Government to set out how it will make this broken market work better once and for all."
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