Belsize Park residents are rallying against a roof extension that would see new homes built atop their building, which they say would ruin its "unique aesthetic features".

A planning application was submitted by freeholder Freshwater on September 24 to build seven flats on a 1930s Art Deco block in Howitt Close.

Resident Sally McFall said the plans would have a "severe impact" on people's quality of life, describing them as a "travesty".

She said: "We learned about this planning application from a tiny announcement hanging from a lamppost – discovered more or less by chance by a particularly observant resident leaseholder – notifying those affected that they had just three weeks to comment and object to an application that would turn our lives upside down."

Camden Council said pre-application advice was requested twice prior to the submission of the application, a process "encouraged by national planning policy".

Consultation was then carried out, the council said, including notices in local press and one locally to the site. A council spokesperson said: "There seems to have been good awareness of the application as to date the council has received 60 objections and eight comments on the application.

"All these views are being considered. The application is still being assessed by officers and no decision has been made on the recommendation."

Objections to the application include from The Twentieth Century Society, which campaigns for "outstanding buildings", because of the "harm caused to a non-designated heritage asset and to the character of the conservation area".

The Belsize Society claims the proposal will damage a "well-preserved, unique 1930s building of considerable architectural merit and significance".

A planning statement submitted by Freeths, the agent for Freshwater, said the development provides an "appropriate design response to the existing building whilst maximising the use of the land and delivering much need housing for the area".

It added: "The design of the mansard roof respects the buildings key features, including the projecting cantilevered eaves, and creates a design which is sensitive to the building and the setting of the conservation area."

Sally said Howitt Close is unique in both its architecture and history. Over the years it has housed civil servants, Jewish refugees fleeing the Nazis, and Winston Churchill reportedly visited his war cabinet there.

Comments can be made until November 17 on Camden's planning portal using reference number 2021/3839/P.

Freshwater, via Freeths, was contacted for comment.