The number of UK children living in fuel poverty has risen to 1.6 million - 130,000 more than in 2010, according to a study.
The figure, which includes 1.2 million children in England, is a 9% increase over the past three years, research by the fuel poverty alliance Energy Bill Revolution found.
The group is calling on prime minister David Cameron to "end the growing scandal of cold homes" by using carbon tax to make all homes in the UK energy efficient.
The study estimates that funding to help fuel-poor families with children has been cut by 27% since the government came to power.
A campaign to accompany the study claims that children living in cold homes are twice as likely to suffer from asthma and other respiratory problems compared with those whose families can afford to keep the house warm.
The Energy Bill Revolution said there was enough carbon tax revenue to deliver energy efficiency measures to more than half a million fuel-poor homes every year.
It claims its proposed improvements to energy efficiency would cut the bill of the average fuel-poor household by more than £300 every year, bringing nine out of 10 homes out of fuel poverty.
Energy Bill Revolution director Ed Matthew said: "Fuel poverty is a nationwide scandal that is forcing some families to make the desperate choice between heating their home or feeding their family this winter. The only permanent solution to the fuel poverty crisis is for the government to invest in a nationwide programme of super-insulation funded by carbon tax, which could end fuel poverty once and for all."
Barnardo's assistant director of policy and research, Neera Sharma, said: "It's a disgrace that not only has so little action been taken to bring down energy bills, but nothing is being done to stop them rising further for the UK's poorest families.
"Now 1.6 million children endure the misery of growing up in cold homes, which can affect every area of their wellbeing.
"The government must tackle this national crisis to reduce the effects of poverty. They can start by channelling funds raised by the carbon tax into making homes warmer."
A Department for Energy and Climate Change spokeswoman said: "We can't control volatile world energy prices, but we are working with the independent regulator, suppliers and consumer groups to help people keep bills down this winter.
"We have schemes in place to improve energy efficiency and tackle fuel poverty, including subsidies for the poorest paid for by suppliers, and the Green Deal launched at the end of last month will help millions improve their homes so they are better insulated, with extra help for those who need it most.
"Energy policies are already benefiting from direct funding from the Exchequer, including the £1 billion for carbon capture and storage, £860 million for the renewable heat incentive, which will also help households that are off the gas grid, and £200 million in Green Deal incentives."
Shadow energy secretary Caroline Flint said: "These figures are a damning indictment of David Cameron's failure to get a grip on spiralling energy bills.
"People have to ask themselves what kind of Government can afford a £3 billion pound tax giveaway for the highest earners but chooses to cut support for people in fuel poverty and leave over a million children in the cold."