Nearly four million households are expected to fall into fuel poverty this year, according to the Department of Energy and Climate Change (Decc).
The number of UK households in fuel poverty dropped from 5.5 million in 2009 to 4.75 million in 2010, new figures show. But the improvement is not expected to continue.
The rise in energy prices last year is expected to increase the number of households in fuel poverty again, although the figures will not be published until 2013 and 2014, Decc said.
Projections for England indicated there were likely to be around 3.5 million fuel-poor households in 2011 and 3.9 million in 2012.
The reduction was mainly due to rising incomes, relatively stable energy prices at the time and reduced energy consumption, according to the 2012 Annual Report on Fuel Poverty released by the Decc.
Northern Ireland remains the most fuel poor part of the UK, with estimates suggesting 44pc of households spend more than 10pc of incomes on energy bills.
In Scotland, 28pc of the population are fuel poor, Wales is at 26pc but England drops to 16pc.
Energy and climate change minister Greg Barker said: "I am encouraged by the fall in fuel poverty in the period to April 2011, but there is no room for complacency.
"Fuel poverty remains a serious national problem and the Coalition is absolutely committed to tackling it.
"People can still get help with heating and insulation through Warm Front and around two million households will get money off their energy bills this year through the Warm Home Discount scheme.
"However, our ambitious new policies including the Green Deal will go much further.
"The Green Deal will help people pay for home improvements through savings on their energy bills with extra financial help for the most vulnerable."
Michelle Mitchell, Charity Director General of Age UK said she was pleased the fuel poverty figures had fallen after six years of annual rises, but the evidence suggested the good news was just a temporary interruption in a steady upward trend.
"Living in fuel poverty is miserable. It leads to serious health problems and at worst kills people," she said. "The independent Hills Fuel Poverty Review said that even if only 10pc of excess winter deaths are due to fuel poverty that would be more deaths per year than the fatalities on our roads."
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