Ugly air conditioning units on top of a university building has "destroyed" one of Kent's most iconic views, according to a local historian.

And a proposed remedy to screen the unsightly units blocking sights of Canterbury Cathedral has been blasted by a conservation body.

Despite a six-page explanation by agents for Canterbury Christ Church University, Historic England is objecting, saying the supporting information "falls short of the quality and level of detail required" to assess its impact.

The university has been forced to find a solution after installing the 10ft high plant equipment on the roof of its new £65 million STEM building without planning permission. It is now seeking approval for the screening it is proposing.

But critics, who complained the plant was a blot on the skyline, ruining heritage views across to the Cathedral, are still unimpressed.

City historian Hubert Pragnell recently visited St Martin's churchyard to photograph and paint the view across to Canterbury Cathedral.

"I do not exaggerate the significance of this view from one of our World Heritage Sites to another, depicted in paintings and photographs from the 19th century onwards," he said.

"You can imagine my exasperation when I was confronted by the way the view has been ruined by the large building of Christ Church University blocking a large proportion of the quire of the Cathedral.

"Concern has been expressed about the addition to the roof of the air filtration apparatus, which increases the height of the visual destruction which, of course, compounds the situation."

Dr Pragnell says he understands the need for the university to build as part of their development, but questions why to such a height.

"The city council planning department should have been cognisant of how visually destructive the granting of planning permission would be and this viewpoint should have been protected, just as the view of St Paul's Cathedral is protected from certain viewpoints, including from Richmond Park, over seven miles away," he said.

Now, Historic England has concluded it cannot accept the application for the rooftop plant screening in its current form - while acknowledging the university's "willingness to find a solution" which avoids or minimises harm to views of the city.

Its objection will be seen as a setback by agents for the university who hope the remedial measure will be acceptable.

In their application, they argue the development will have a "negligible affect" on the quality of the view, especially from St Martin's Church, due to a "significant thick tree belt".

They also say the rooftop air handling units will be repositioned and a series of screens erected to obscure potentially detrimental views.

In their application they conclude: "The proposed development enhances views, reinforces the character and identity of Canterbury Christ Church University and Canterbury, and does not detrimentally affect the World Heritage Site, conservation area or listed buildings."

A university spokesman said this week: "The university is continuing to work with Canterbury City Council and consult with other key local stakeholders on the planning application and screening of the air handling unit on The Verena Holmes Building."

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