Available through MoneySuperMarket only, the EDF one-year fixed rate tariff is open to new EDF customers and will cost on average £724 per year, which according to the comparison site makes it the cheapest current tariff on the market.

Based on dual fuel, the monthly direct debit tariff is £339 cheaper than the average Big Six standard money direct debit energy bills, with the average standard variable tariff of these providers coming in at £1,063.

The tariff is fixed from the start of supply until 31 May 2017 and will be available to take out until Friday 20 May 20, or for the first 25,000 customers. All customers switching to the one-year fixed tariff should note they will be charged an early exit fee of £25 per fuel if they subsequently leave EDF within the 12 month period.

Stephen Murray, energy expert at MoneySuperMarket, said: “Moving to a fixed tariff, such as this EDF one, means customers know the price they’ll pay for gas and electricity will stay the same for the duration of the contract, unlike a variable tariff where the rate can go up and down.

“It is the price of the gas and electricity units that’s fixed and not the size of the bill, so while the amount customers have to pay will vary according to usage, these are the cheapest duel fuel prices on the market.”