Those living close to a station car park that could be redeveloped to provide almost 130 flats have urged their council to block the proposals.
Residents of High Worple, Rayners Lane, and the surrounding roads voiced their opposition to plans set to be put forward by Transport for London (TfL).
The scheme, in Rayners Lane Station car park, aims to provide 100 per cent affordable housing across 128 flats.
But those living nearby are concerned about the impact the development would have on traffic, infrastructure and the car park, which could lose 170 spaces.
They are also opposed to the scale and design of the buildings and urged Harrow Council’s planning committee to reject the project.
In a statement, campaigners said: “They are trying to build too much in too small an area.
“The plan utterly fails to meet the needs of the residents, the businesses, and the visitors to Rayners Lane.
“Cramming hundreds of new residents into many dozens of homes will add to the pressure on local infrastructure and public services which have already been affected by other recent large property developments.
“The huge structures dwarf anything else and will ruin the privacy of numerous family homes.
“Rayners Lane’s habitability and prosperity relies on the planners striking the correct balance between population density, transport facilities and other infrastructure. The car park is essential: the proposal is not.”
They have the support of Harrow West MP Gareth Thomas and launched a petition last year to highlight any public opposition to the plans.
The scheme, which has sister projects in Stanmore and Canons Park, also came under fire at a council major developments panel last year.
Those behind the project have been keen to highlight its positive aspects and said they will continue to try and provide a development that fits in with residents’ aspirations.
The Mayor of London, Sadiq Khan, said the scheme will “offer a great opportunity to provide the genuinely affordable homes that Londoners desperately need, while also generating vital revenue to reinvest in the transport network”.
He added that reducing the number of car park spaces will encourage sustainable travel which will “address local congestion”.
TfL, in partnership with housing association Catalyst, aim to put forward planning applications within the next few months.