Some of the poorest families in Britain may struggle to keep their homes warm as they cannot afford all the gas and electricity they require.
Research by Barnardo's found households in the bottom ten per cent of incomes typically need to spend £1,165 a year on fuel, but the average actual expenditure for these individuals is just £723.
The charity said this "fuel gap" could be potentially detrimental to the health and well-being of the UK's poorest families.
Chief executive of the group Anne Marie Carrie said: "Many of the families Barnardo's works with are bearing the brunt of companies' unfair tariffs because they are using pre-payment meters to pay off their debt and to pay for gas and electricity."
The organisation therefore called on energy suppliers to bring down their tariffs for these meters to match their online and direct debit offers.
Recently, the Daily Mirror reported households that owe £200 or more on these arrangements are often prevented from switching energy supplier due to their debts.
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