The court found that a modification to the approved Littlewoods Estate development was granted consent without proper processes in place by the council.

The modification involved increasing the number of lots on the property from 24 to 25 and the adjustment of internal lot boundaries.

The ruling has been claimed as a victory by the Friends of Glebe Wetlands group, whose members filed the challenge in the Land and Environment Court.

The Friends of Glebe Wetlands have previously raised concerns about the impacts of the development on the neighbouring grey-headed flying fox colony.

A spokesman for the group, Hugh Pitty, said "had the modification to the consent granted last year been allowed to stand, the construction of new residential dwellings would be allowed far too close to the long-established flying-fox camp".

The proximity of the approved development to the flying-fox camp was not in question in the Land and Environment Court matter, just the process council underwent in consenting to it.

Justice Rachel Pepper handed down her orders on Monday, March 21.

In her published findings, the judge said the consent was "invalid, void and of no force and effect" and made an order that the decision to grant consent was "quashed".

"The making of the declaration marks the disapproval of the court of the conduct of the council in not ensuring that appropriate delegations were in place," Justice Pepper's ruling reads.

"It will serve to encourage this, and other councils, to implement and follow proper processes in respect of the issuing of delegations so that decisions are made with the necessary statutory power to do so.

"As a matter of fact and law Friends of Glebe have succeeded in its judicial review challenge because of the jurisdictional error made by the council in approving the modification application absent power to do so," the judge's ruling reads.

"Littlewoods played no role in the decision to unlawfully modify the consent. This is directly reflected in the costs orders made by the court."

The BVSC said the court ruling does not affect the original development consent. It said it was "engaging with the proponent to correct the error that led to this judgement".

"This process would involve further opportunity for community input," the council said in response to ACM queries.

Read more Court coverage here