The cheapest fixed energy tariff has been launched by a Big Six supplier.

SSE’s new deal costs £899 a year on average, with the price fixed for 12 months.

The news follows the Competition and Markets Authority’s (CMA) investigation, which revealed energy customers have been paying £1.7 billion too much for their gas and electricity.

The average Big Six standard variable tariff is £1,237, according to price comparison site uSwitch.

Ann Robinson, Director of Consumer Policy at uSwitch said: “Small suppliers have ruled the roost in the best buy tables over the last year so this new deal could be the firing pistol for an industry price war.

“Is today’s move by SSE designed to lay down the gauntlet to the other big suppliers to do more to help customers tackle high bills?”