Households with prepay energy meters are weighed down by more than £1billion of debt, say campaigners.
Repayments are deducted from credit and can deny households energy they need for heating, cooking or medical equipment.
Junnie Braithwaite, 56, from North East London, is among those affected. She said: “I live in a socially rented apartment over two floors and need a stairlift because of fibromyalgia and arthritis.