A £1.75m valuation put on a Victorian building under threat of demolition was never obtainable, the High Court heard today.
Lawyers for heritage campaigners seeking to stop destruction of the Athetic Stores building in Belfast city centre argued that its true worth was not tested on the market.
Although the 19th century warehouse on Queen Street is not listed, it is situated in a conservation area.
Last year the Department of the Environment gave fresh permission for its demolition to make way for residential and retail redevelopment.
Serious structural flaws in the building and the disproportionate cost of repairs were identified.
The decision prompted renewed legal action by the Ulster Architectural Heritage Society.
In 2010 the charity succeeded in getting a previous authorisation for demolition quashed.
Planning chiefs had been ordered to reconsider the application by developer Carlisle Property Developments Ltd to build apartments, ground floor shops and underground car parking on the site.
Counsel for the Department have argued that full consideration was given to all relevant planning issues.
But according to the Society's legal team the latest decision was irrational and in breach of planning policy.
Michael Lavery QC contended that more should have been done to see whether the building could have a future, such as putting it on a market at a price that reflected its condition.
He described an independently reached valuation as "fanciful".
The barrister said: "The justification for not market-testing it... is clearly on the basis that everybody realises there would be no offers for this in the range of £1.75m or anything like it.
"The importance of the £1.75m is that is the cornerstone of the calculation which led to the conclusion of non-viability."
Mr Lavery argued that protection of the environment should take priority over the developer's interests.
"The stakes here are very high. Belfast isn't very rich in buildings of this sort, Northern Ireland's the same," he said.
"Once this building is lost that's the end of it."
The barrister claimed preservation of the building was not on the Department's agenda.
He told the court: "It wasn't save this build, but let's justify its demolition."
Following submissions Mr Justice Treacy reserved judgment on the application for judicial review.
He pledged to give his decision as soon as possible.