The campaign against Stoke Newington’s new Sainsbury’s development will be brought to the Court of Appeal.
Activists’ hopes were dashed after the Wilmer Place project was given the go-ahead by the High Court.
But 60 members of the Stokey Local campaign voted unanimously to continue the fight against Hackney Council.
The group needs to raise a further £14,000 on top of the £25,000 it has already received from donations and fundraisers, but lawyers will continue to represent the campaign free of charge.
The campaigners argue that the 4,100 square metre Sainsbury’s store will harm local biodiversity, undermine the area’s conservation efforts, and damage local businesses.
The five floors of housing above the development will also only fulfil 17 per cent of the 50 per cent affordable housing that Hackney Council aims to provide in new developments.
Stokey Local is now looking for volunteers to run street parties, a battle of the bands event, and an auction of promises in a bid to raise more funds.
“Three years into this campaign, it seems as if the community is determined to take this to the limit,” said a representative of Stokey Local.
Campaign leader Nick Perry said: “I am really buoyed by the massively supportive turnout tonight.”