A 100-year-old legal covenant could thwart plans for a £94m shopping development in the centre of Dartford.
The regeneration plans for Dartford were approved by the council
Local residents claim building cannot go ahead on an area that includes Central Park as it was left to the community for recreational use.
Derek Maidment claims Dartford Borough Council is failing in its duty to protect the four and a half acres of land donated by Charles Kidd in 1903.
The council said it remained confident the regeneration would still go ahead.
Councillors approved the plans for Central Park last August as part of a multi-million pound regeneration scheme for the Kent town which will see a two-lane road cut through the middle of the park.
Plans were agreed for hundreds of new homes and a supermarket, despite a petition signed by 13,000 people.
The council wants to build on an acre of Mr Kidd's land, but a document signed between him and the local council in 1903 states it is only to be "appropriated and used as a public recreation ground, and for no other purpose whatsoever".
Mr Maidment, who lives in the town, insists the land belongs to the people of Dartford, and not to the council, which is "persisting" in trying to take it away.
"It is a jewel in the crown of Dartford, but it is going to be desecrated by a big store and a big road," he said.
In a statement, Dartford Borough Council said: "This is a complex legal issue that the council has looked into and are very confident that this much needed regeneration will go ahead."
A public inquiry into the development by the Office of the Deputy Prime Minister is due to be carried out later this year.