WINCHESTER City Council has been ordered to publish information which led to the developer of Silver Hill claiming a previously proposed £165 million scheme was commercially viable.

The Information Commissioner has said civic chiefs failed to meet the public interest when it withheld financial data on the grounds of commercial confidentiality.

Details to be released, including developer TH Real Estate's overall costs and profit, relate to the 2014 scheme which has been defeated in the courts - swapping a bus station and cut-price flats for more retail.

It comes after a Freedom of Information request made by an anti-Silver Hill campaigner in December, while the 2014 plans were still alive.

The commissioner found that the "majority of this information" is rightly confidential but some must be disclosed in the public interest.

Figures to be released include the net development value and developer TH Real Estate's profit forecast as well as market values of flats in the scheme, broad construction costs and car parking details. Finer details to remain confidential include estimated shop rental values, land prices and specific construction costs on the grounds that they would prejudice commercial negotiations with the developer, formerly known as Henderson.

Winchester Deserves Better leader Cllr Kim Gottlieb said: "With the stuff that [will be] released, you can reconstruct the whole thing anyway."

Information Commissioner Christopher Graham said disclosure will allow the public to "understand whether the council had managed the proposed redevelopment in a competent manner" over architecture or the loss of affordable housing.

He said: "The commissioner is not satisfied that the council has attached sufficient weight to the public interest in disclosing the information.

"There are a number of factors which greatly increase the value in disclosing information on the decision making process and in particular on the spending of public money and whether the council obtained the best deal for the community it serves."

Judith Martin, the campaigner who filed the request, said: "Like a great many people, I wanted to know why, in their 2014 proposal, Henderson dropped the obligation to provide the 100 affordable homes as well as other aspects of the social element of the development that had been previously agreed.

"The council accepted the developer's claim that the social benefits made the scheme unviable, but refused to provide any financial details."

Details which could prejudice the 2009 scheme set to go ahead, restoring the bus station and affordable flats, will not be disclosed.

But council leader Cllr Stephen Godfrey said he hoped "greater clarity" on the rules would set a precedent for transparency over the 2009 scheme.

He said: "It has been a question for local planning authorities for some years about what information should be disclosed publicly and to the planning committee about the viability assessments. The information the commissioner has made gives some clarity to that.

 “We do not anticipate any commercial impact from the requirement to disclose high-level summary information such as the net development value and profit by 22 October.

 “This report may set a precedent for information that needs to be disclosed about other viability assessments in the future and that is something we will look at carefully.”

Asked whether the council should have done more to establish what was in the public interest, he added: "If you want to keep a secret, you don't tell anyone you've got it."

The council has been ordered to publish the information by October 22.

It comes amid further delays to an independent report into the council's unlawful handling of the scheme last year. Solicitor Claer Lloyd-Jones is expected to shed light on how the 2014 scheme was kept from public tender in breach of European procurement law.

The report was originally due by June, then delayed until this month.

The council has received no further indication of when the report will arrive, a spokesman said. Asked whether it will be made public, he added: "The report will be considered by cabinet and council."