The pounds 200 plastic front door that cost the taxpayer pounds 10,000

English Heritage officials spent pounds 10,000 on a failed legal action to force a woman living in a Derbyshire Dales conservation area to change her pounds 200 plastic door, it emerged yesterday.

Patricia Harman, 53, has fought for two years to retain a wood-effect UPVC four-panelled door, installed at her mid-terraced home in the village of Wirksworth. And yesterday, a High Court judge rejected English Heritage claims that a Department of the Environment planning inspector was wrong in law not to declare the door "unsuitable".

The judge also rejected the conservation body's claim that allowing it to remain would create a precedent which could jeopardise efforts to preserve the character and appearance of buildings in conservation areas around the country.

In the first case of its kind, Deputy Judge Moriarty QC said: "In my judgment, the criticisms made are not borne out on a fair reading of the decision letter."

Patrick McLoughlin, Tory MP for West Derbyshire, said the English Heritage action had been pointless and wasteful. "This was an absurd waste of money. There are better things to spend money on and I am rather appalled at the way English Heritage have hounded a constituent of mine."

However, Dr Anthony Streeten, head of English Heritage's East Midlands conservation team, said it was money well spent. "It is not pounds 10,000 wasted because it has given us the very full airing that we were seeking of the issues involved," he said. "Our fundamental concern is not a resistance to plastic. It is that we don't consider you can achieve the subtlety of treatment, of texture, of detailing, in plastic that can be achieved with the traditional craftsmanship in finishing a traditional door."

He said English Heritage was happy that the court had treated the case as a "one-off" that would not allow other homeowners in conservation areas to make similar changes to their properties.

"Counsel for the Secretary of State made it very clear that they did not consider this particular inspector's decision to create a precedent," he said.