The £30million needed to upgrade the “ancient and inefficient” Kneller Hall includes more than £200,000 to demolish existing buildings and £21m for new buildings, a Freedom of Information request has revealed.

The Ministry of Defence contacted Richmond Council earlier this year about the possibility of building 192 homes on the Royal Military School of Music site, which it has earmarked as part of a plan to sell off underused buildings.

FROM FEBRUARY: Defence minister reveals Kneller Hall is earmarked for 192-property development

Defence minister Mark Lancaster said the cost of refurbishing the hall, named after the Kneller family, would be £30m, and the FOI provides a base estimate of £28.2m.

The news was met with opposition from Richmond residents and Twickenham MP Tania Mathias, who argued the 150-year-old mansion was the “heart and soul of Whitton."

An online petition on Change.org to calling for the hall to remain open reached 5,374 supporters.

The FOI stated it would cost £100,000 to demolish two accommodation blocks and £14.7m to build “single living accommodation”.

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The Kneller Hall Military Band during the St George's Day parade

Refurbishing the officer’s public rooms would cost £495,000 and building band practice rooms would cost £1.2m, according to the Ministry of Defence.

Dr Mathias said the figures would need further scrutiny in order to justify why a refurbishment could not be considered over the sale.

She said: “I am very disappointed that it took an FOI request to get this information out, when we were promised this by the MoD at the public meeting I organised.

“The figures clearly need further scrutiny, but more than anything it saddens me that such an important site as Kneller Hall has clearly not received the resources it required over a period of many years, despite promises to the contrary.

“Our fight to save the hall continues.”

The national media reported in March that the Rugby Football Union (RFU) was discussing bidding for Kneller Hall with the intention of turning the site into a rugby academy.

The RFU has not confirmed this, however.

A spokeswoman from the Ministry of Defence said there was no update with regards to the site’s future.