Martin Lewis has warned millions in the UK face losing up to £400.

The Money Saving Expert founder was took to social media to warn his 1.2 million Twitter followers about a a predicted 30% energy bill rise.

Research agency Cornwall Insight has predicted further volatile gas prices and the potential collapse of even more suppliers could push the energy price cap to about £1,660 in summer.

Martin Lewis warning over £400 losses

Martin Lewis tweeted: "The current 1 Oct - 1 Apr energy price cap is £1,277/yr (on typical use.) The assessment period for next cap starting 1 Apr is Aug - Jan.

“I've just asked @cornwallinsight and it predicts cap will then rise to £1,660 at current run rates. Many will be desperate."

In response to the concern, the cash-saving guru went live on social media for the first time to answer questions from concerned consumers.

The forecast is approximately 30% higher than the record £1,277 price cap set for winter 2021-22, which commenced at the start of October.

Craig Lowrey, senior consultant at the firm, said: “With wholesale gas and electricity prices continuing to reach new records, successive supplier exits during September 2021 and a new level for the default tariff cap (£1,277 for a typical dual fuel direct debit customer) for Winter 2021-22, the GB energy market remains on edge for fresh volatility and further consolidation.”

Ofgem issue statement over rising energy bills

Energy regulator Ofgem reviews the price cap once every six months, and changes it based on the cost that suppliers have to pay for their energy, cost of policies and operating costs, among other things.

In a statement to the BBC, Ofgem acknowledged it was a “worrying time for many people”.

The regulator added: “The energy price cap covers around 15 million households and will ensure that consumers don’t pay more than is absolutely necessary this winter.

“However if global gas prices remain high, then when we update the price cap unfortunately the level would increase.

“Any customer worried about paying their energy bill should contact their supplier to access the range of support available.”