The charity said its research shows pre-payment customers pay an average £80 per year more than direct debit customers and get much worse customer service. Citizens Advice’s campaign Fair play for prepay is urging energy companies to offer a better price, more control, and easier ways to use pre-payment meters.

Gillian Guy, chief executive of Citizens Advice, said: “Prepayment customers pay more money for a second rate service. As well as facing great inconvenience when topping up, customers pay on average £80 more than those using direct debits. The launch of Smart PAYG+ is an encouraging development and hopefully it will kick-start some further competition into the prepay market.”

Smart PAYG+ is an app which allows customers to manage their energy use and top-up online at any time and any place.