A petition has been launched to save what campaigners claim are London's oldest allotments from development.
Northfields Allotments in Ealing were established in 1832, according to plot holders, which they say makes them the capital's most historic.
The charity Pathways, which owns the land in Northfield Avenue, has announced plans to build on around 10% of the allotments to create more social housing for vulnerable older residents and improve the flats it already provides.
It claims the affordable homes, which would be available at half the normal market rent, are needed due to an "acute shortage" of affordable housing for senior citizens in Ealing.
But allotment holders and politicians have rounded on the plans which they say will destroy a "key community asset" and a valued part of the borough's green heritage.
A petition by local councillors in the Walpole ward had already been signed more than 300 times by Thursday (September 8) morning, having only been launched the previous afternoon.
'Ancient allotments are nature conservation area'
Christina Fox, chairwoman of the Ealing Dean Allotments Society, which manages the site, said: "There's no doubt we need more social housing in London, but we need green space as well.
"These are ancient allotments, which have been recognised as a site of importance for nature conservation and as a designated community open space.
"For a lot of people who would lose their plots, this is their only green space. It's their garden, and somewhere they can go to wind down and relax.
"It's also a breeding ground for stag beetles, which are an endangered and protected species."
She added that the claim to be London's oldest allotments had been backed up by a professor at the University of Reading, who is a leading authority on allotments and said he knew of none older within the capital.
She said there are 141 allotments at the site, with around 70 people on the waiting list and an average waiting time of two-and-a-half years to secure an allotment.
'New homes needed to help vulnerable older people'
Pathways' proposals, which it says are at a very early stage, would see 56 existing homes at Dean Court replaced with more modern facilities.
It also plans to create 54 new social homes and 30 homes for private sale, which would help to fund the scheme.
That would include 18 social homes and four homes for private sale on a small section of the allotments site adjoining Mattock Lane, with those buildings rising as high as five or six storeys.
Clive Wilson, chief executive of Pathways, said: "There is an acute shortage of affordable housing for older people in Ealing, and demand is increasing all the time.
"We believe that the redevelopment of Dean Court would mean that we could not only deliver new homes for all the current residents, but also provide the chance for other older people in need to live in an affordable, secure home.
"It's about providing much-needed affordable housing while minimising the disruption for allotment holders."
He added that some of the existing flats at Dean Court were so cramped they would not comply with regulations for new buildings.
The charity says 10% is the minimum portion of the allotments site needed to ensure existing residents of Dean Court can be accommodated while their current homes are redeveloped.
Pathways has promised to work with allotment holders to improve facilities on the remainder of the site.
It also says the high turnover of plots means those losing their allotments will not have to wait too long for a new one.
'Hub of the local community'
But Labour councillor Gareth Shaw, speaking on behalf of his fellow Walpole ward councillors, said the allotments site was too important for any part of it to be sacrificed.
"The Northfield Avenue allotments are the hub of the local community, providing much escape from the surrounding urban environment, as well as learning opportunities for younger children about plants, food and wildlife," he said.
"It's an invaluable resource that we appreciate. Our residents are fortunate to have such an open space but for many of these allotment holders, it has been a labour of love, not just for a few years but for decades.
"For these reasons we must do all we can to protect this allotment from being developed."
Rupa Huq, MP for Ealing Central & Acton, said: "I've spoken to committee members of Ealing Dean allotments and understand their legitimate concerns.
"I'm meeting with Pathways to determine precisely the detail of the plan but I am opposed to the destruction of this vital green space which has provided plot holders so much for so many years."