The planning permission granted by the council allows a temporary change of use for part of the park, covering a period of up to 32 days.
In written submissions, Richard Harwood KC, for Juliet Chambers, said the granting of planning permission was “unlawful”.
Sasha White KC, representing Lambeth Council, told the court: “During the events the rest of the park will be retained as public open space, therefore leaving 74% of the park open to the public throughout this period.”
White added that assessments suggested no “unacceptable harm” would arise as a result of planning permission being granted, and that nine individual benefits had been identified.