Friends of the Earth and Help the Aged are to file an application for a judicial review, saying the Government has failed to come up with a plan to meet its targets.

The charities are campaigning for improved domestic energy efficiency to end fuel poverty and tackle climate change. A household suffering from fuel poverty is defined as one which spends more than a 10th of its net income on electricity and gas.

The Government has committed itself to the legally binding target of eradicating fuel poverty among vulnerable households in England by 2010, and across the UK entirely by 2016. Ministers recently admitted there may still be 1.2 million vulnerable households in fuel poverty in England by the target date.

Ed Matthew, low carbon homes campaigner at Friends of the Earth, said: "By failing to back the highest levels of energy efficiency in the homes of the fuel poor, the Government has missed an opportunity to both end fuel poverty and bring down carbon emissions.

"Its strategy is incompetent and lacks vision. Today we take the Government to the High Court to make it put an end to the misery of fuel poverty."

Mervyn Kohler, special adviser for Help the Aged, said: "The Government's fuel poverty strategy is a fiasco and all too often older people are the casualties.

"For those living in fuel poverty, the daily reality often means pain and misery, illness and even death.

"When fuel costs fell the Government was happy to take the credit for falling fuel poverty figures. Now that the energy market has changed and the importance of domestic energy consumption has grown, it must take responsibility for its inadequate and passive response."

The two charities have called on the Government to set out out how it plans to meet its targets and how much it will cost, and to find a way of identifying all households suffering from fuel poverty.