Ofgem has launched the investigation to see whether prepayment meter customers were charged above the price cap between May and September 2019.

The pre-payment meter price cap came into effect on 1 April 2017. It sets a maximum price that suppliers can charge, but not a maximum bill. The amount customers will pay under the price cap depends on how much energy is used and where they live.

Between 1 April and 30 September 2019, the cap was set at £1,242 for a dual fuel prepayment meter customer though currently stands at £1,217 until 31 March 2020.

Ofgem said that by opening the investigation, it does not imply it has made any findings about non-compliance by Utilita.

A spokesman, said: “We are aware Ofgem has opened an investigation and will assist the regulator in every way we can.”

Utilita was founded in 2003 and has a total of 780,000 energy customers.