Campaigners have failed in a High Court bid to force the UK Government to spend more to end fuel poverty.

A senior judge ruled yesterday that government departments were not legally obliged to take action "whatever the cost".

Mr Justice McCombe, sitting in London, dismissed an application for judicial review brought by Friends of the Earth and Help the Aged to force the government to meet targets for helping millions of vulnerable citizens who cannot heat their homes adequately.

The pressure groups said fuel poverty was "a blight upon society" and five million households are expected to suffer its consequences this winter.

Even though they lost their legal challenge, they later called on the government to do more to help the fuel poor.

A fuel poverty strategy was introduced under the Warm Homes and Energy Conservation Act 2000 with the stated intention of doing everything "reasonably practicable" to end fuel poverty among vulnerable households by 2010 and in all households in England by 2016.

Critics accused the Department for Environment, Food and Rural Affairs (Defra) and the Secretary of State for Business Enterprise and Regulatory Reform (BERR) of taking insufficient measures to meet their commitments and said the courts should intervene.

Government lawyers argued the departments were doing their best in the face of budgetary constraints and dramatic increases in energy prices, and there had been no breach of legal duty.

Mr Justice McCombe said the government had taken up the challenge to eliminate fuel poverty by specifying that it would try, so far as reasonably practicable, to achieve the targets.

He added: "In doing so, it imported a statutory duty to make those efforts. It did not assume a statutory duty to achieve the desired results, whatever the cost."

Later, Friends of the Earth's head of UK climate Ed Matthew said: "The High Court's decision reveals a huge loophole in the legal protection for people in fuel poverty - big enough for over millions of households to fall through.

"Today's ruling means that it can spend pretty much what it likes and implement a strategy which is seven years old and very vague, making the warm homes legislation almost worthless.

"We need a proper plan that makes sure that every home struggling to keep warm is properly insulated."