THE cost of lowering the controversial Castle Mill student buildings could be up to £20m, it has been suggested.

But Oxford University has already ruled out spending the money because it would be an “inappropriate use of charitable funds”.

In a letter to Michael Crofton Briggs, Oxford City Council’s head of development, the university’s estates director Paul Goffin said it would be happy to consider further work in addition to the trees it had already agreed to plant in Roger Dudman Way.

This could include landscaping and the creation of so-called “green walls” which are completely covered in vegetation – an idea successfully implemented in Madrid and Mexico City.

He said: “The university is a charity, with the objective of the advancement of learning by teaching and research. “It would be an inappropriate use of charitable funds to incur costs of this magnitude in relation to a scheme which has planning approval.”

He added it was not practical to flatten the pitched roofs to reduce the height since they contained vital services for the buildings.

Mr Goffin said: “Making such major modifications at this late stage to the largely completed buildings will have major cost implications.

“We have not undertaken any detailed work, but the costs will be significant and certainly between £10m and £20m.”

The buildings have caused widespread protest from campaigners who say they block views of Oxford’s “dreaming spires” from Port Meadow.

Though the Castle Mill development was given planning permission last year, it has emerged a heritage officer warned about the potential impact before a decision was made.

While the university will not volunteer to lower the buildings, the city council does have the power to ask the Secretary of State to withdraw planning permission. But to do so would leave it open to a compensation claim from the university.

Toby Porter, who is leading the campaign against the buildings, said he was “extremely disappointed”.

He said: “The letter in our eyes confirms that the university has to all intents and purposes been ‘filibustering’ for the entire past six months.

“They have ploughed ahead with the construction, offered not even one compromise to any feature of the design of these ruinous blocks, and shown themselves apparently completely indifferent.”

Mr Goffin’s letter is included in a report put together by Mr Crofton Briggs which is being presented to a committee of city councillors next week.

The report will be considered at a public meeting by the west area planning committee on Wednesday, April 17, at 6pm in Town Hall.