Campaigners fighting proposals to build what would be one of the tallest towers in Camden urged the communities secretary to throw out the scheme, saying it will “photobomb” the local area.

An eight-day public inquiry into the controversial £100million project by developers Essential Living ended last week, with planning inspector Graham Dudley hearing closing remarks from those in favour and against.

Rejected by councillors in September last year, it would see offices at 100 Avenue Road, in the heart of Swiss Cottage, torn down and replaced by an enormous 24-storey tower visible from Hampstead Heath.

Some 3,000 people have objected to the project, with designs described as “monstrous” and “casting a blight on the whole area”.

Neil Cameron QC, speaking on behalf of Camden Council on Monday, urged the planning inspector to reject the scheme, saying it would have a harmful effect on six surrounding conservation areas; cause the neighbouring Swiss Cottage Open Space and market to be left in the shadow; and have a harmful impact on neighbouring listed buildings.

He said: “The proposal will affect a large number of people for an indeterminate period in the future.

“While it will bring benefits, so did many developments which were soon regretted.

“The benefits do not begin to outweigh the harm.

“The heritage interest created over the many years, and over a wide area, should not be compromised by allowing this development to proceed.”

Mr Cameron also expressed his disbelief at claims made by the architect of the scheme, Craig Casci, that people using the neighbouring open space will not be affected by the visual impact of the tower because they “will not look up”.

Lawyers representing Essential Living argued the scheme would bring a number of benefits, including providing 184 privately rented flats (54 of them affordable); a new home for charity The Winch; and landscape and public realm improvements.

They said: “This is the kind of scheme that drives progress in London. The proposal will transform the site and will be the latest in a series of modern buildings.

“It would represent another organic change [to the area].”

The final day, held at Camden Town Hall, also saw a number of local residents groups speak out against the scheme, with some saying the tower would “photobomb” the surrounding views - a term used for someone intentionally ruining a photograph.

The evidence heard will see Mr Dudley have to weigh up whether the visual impact of the building will be substantial and, if so, whether the public benefits outweigh the harm caused.

A timetable for a final decision, to be made by the communities secretary Greg Clark MP, is set to be agreed next week.