Gas prices will increase by an average of 9.5 per cent, while electricity prices will go up by average of 8.4 per cent from 1 December.
The company, which was formed in 2003, blamed “big increases in distribution charges” and the “constantly rising” cost of government obligations.
In a statement on its website, Utilita said: “We understand the impact a price increase has on our customers; we do not take this decision lightly and will continue to do everything in our power to ensure we are the cheapest prepayment supplier in the UK.”