Newham City Farm is closing permanently after almost 45 years.
Chiefs from Newham Council's cabinet agreed unanimously to the closure at a meeting on Tuesday, September 7.
A bid to persuade councillors to let supporters take over the running of the Beckton-based farm opened by Princess Anne in 1977 failed.
At the meeting, Karima Turay from Custom House said: "It's the absolute jewel in the crown. We are one of the poorest wards in one of the poorest boroughs in London.
"We have a duty to our children to make sure they have access to animals."
Cllr James Asser, cabinet member for environment, highways and sustainable transport, apologised to the people of Newham after admitting the farm had been run down to the point where it was no longer fit for purpose.
He explained how allowing another organisation to run the farm - credited as one of London's oldest - had not worked in the past.
Community Links and Active Newham had both tried, but handed the site back.
The meeting heard £7million would be needed to bring it back up to a decent standard after inspections in November uncovered a series of issues, including concerns about some animals. Legal proceedings are underway.
Members of the public seated in the gallery at East Ham Town Hall shook their heads when Cllr Sarah Ruiz said the farm, which is in King George's Playing Field, was inaccessible to children with special educational needs (SEN) and disabilities.
"We have a chance to create something accessible for all the community," she added.
She explained that when members of the council's watchdog environment scrutiny commission visited the farm, they were "shocked and horrified" by what they saw.
Cllr Carleene Lee-Phako said whatever replaces the farm should have children and adults with SEN and disabilities at its foundation.
Green gyms, a play area, veg plots or more woodland could be among plans for the site, which the council has pledged to consult on. The meeting heard animals could form part of the proposals.
Newham maintains the site will remain a green space which is accessible to the public.
In a statement, supporters said they felt "devastated", but wanted to work with the council on plans for the site and parks in Beckton.
However, they added that their campaign to retain Newham City Farm in some form would continue.
"Our fight is not over yet," the statement said.
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