Breckland’s council taxpayers could be forced to pay a “substantial six-figure sum” for the appeal which followed the refusal of a controversial substation plan.

Warwick Energy’s plan for the 32-acre development at Little Dunham, near Swaffham, was rejected by Breckland Council in October due to the potential impact of its 15m-high buildings on the rural landscape.

The councillors’ decision, made against the advice of their own planning officers, was subsequently appealed by Warwick, resulting in the two-day appeal hearing which concluded on Wednesday.

As the meeting closed, Warwick’s planning consultant Chris Brett said Breckland had failed to provide enough evidence to justify its original refusal.

And while the Little Dunham Action Group, led by parish council chairman Simon Fowler, was applauded for its comprehensive argument against the plans, the energy firm demanded its appeal costs to be paid by the district council.

Warwick’s application was made “on the basis that the council has acted unreasonably in refusing permission and has unnecessarily put the appellants to the expense of the appeal.”

Breckland’s lawyers have disputed the claim, saying they had made a clear written case, whose key element had been agreed by the appellant.

Mr Brett said: “A planning authority must provide a strong evidential basis for resisting development and must produce that evidence during the appeal process. That is their responsibility; they cannot discharge that responsibility by relying on third parties.”

Mr Brett said the authority had not provided photographs or montages from sensitive viewpoints to back up the claim that the substation would add “conspicuous and alien” features to the landscape.

The council’s head of legal services Michael Horn said the planning inspector had been taken to see those viewpoints for himself, and that the council’s case had not deviated from the statement it had submitted in March.

He also pointed out that landscape architect Susan Dodwell, speaking on behalf of the energy firm, had conceded there would be a “significant impact” on the area, particularly in the short-term before screening had matured.

Mr Horn said: “We have clearly stated that what we were concerned about was the effect on the immediate location and it has been agreed by the appellant’s own expert witness. She agrees with us, so I completely fail to see how we could be accused of putting forward unsubstantiated assertions.

“The only thing we disagree on when you put all this in the melting pot is whether the benefits of renewable energy outweighs these disadvantages. That is completely subjective.

“I am not embarrassed that our officers took this evidence and reached a different judgement. The council is run by its members and as long as what they decide is logical and rational they have got every right to make that decision.”

Warwick’s project director Mark Petterson said: “We have put nine months of work into this, so it will be a substantial six-figure sum. I feel for the council officers. They were asked to defend the indefensible when they have already agreed that the landscape impacts are acceptable.

“The decision must be based on facts and if planning committees are going to take these political decisions, they must bear the consequences.”

The outcome of the costs application will be published at the same time as the decision on the substation, which will be made by two government ministers. Planning inspector Christopher Frost said the decision is expected to take up to six weeks.