An academic has researched the “emotional impact” of controversial renovations to Henrietta Barnett School and found they have a negative impact on residents.

The all-girls school added modern extensions to its Grade II-listed building in Hampstead Garden Suburb earlier this year.

The �7.75million renovation has now been branded “architecturally and historically inappropriate” by 94 per cent of residents who took part in the research study by Dr Gloria Moss.

The academic, who specialises in design aesthetics and lives in the Suburb, said: “The reaction from people living close by is extreme. Some of those people are very clearly greatly affected in a negative sense by this extension.”

She carried out in-depth interviews with 20 long-term residents after becoming interested in emotional responses to the buildings – the first to be added to the school site in Central Square for more than 60 years.

They were overwhelmingly negative, with one woman who lived nearby even altering her drive home to avoid the modern block.

The North Square resident said in the study: “It makes my heart bleed when I go past it – I think it’s just awful. My concern is what will happen to other buildings in the area and whether it will set a precedent. I think it’s shocking and abhorrent and I try to drive the other way.”

The extension was designed by the architectural firm responsible for the 2012 Olympic Velodrome and won planning approval with the support of the Hampstead Garden Suburb Trust.

The study found that one of the most contentious aspects of the design were the large glass windows in the extension.

They differ from the traditional windows found throughout the Suburb, which are divided up by white wood into smaller panes.

“It’s the only building I can think of in the whole of the Suburb with these windows,” said Dr Moss, who is based at Bucks New University and is a visiting professor at Paris Business School.

“People commented on the absence of panes in the windows because it’s ubiquitous in the rest of the Suburb.

“In the course of planning works, people say that they’re not allowed to do anything at all radical. Anything they do to their homes has to be extremely close to the original. People can’t quite understand how this building happened.”

A Henrietta Barnett School spokeswoman said: ‘‘We have not seen the study, so we can’t comment on it, but we waited for quite some time to make improvements to the school facilities and we are delighted to have been able to do so.’’