The ruling was one of the rare cases where an individual owner or director of a company was successfully prosecuted for breaching heritage law, and could set a precedent for other Sydney councils fighting to save heritage buildings.

"What often happens is that developers hide behind their company, but in this case the council directly pursued the owner of the company," said Leichhardt mayor Rochelle Porteous.

Cr Porteous said the landmark decision sent a strong message to developers who attempted to flout heritage laws.

"We wanted to send a message that heritage matters. The demolition and removal of buildings and other structures must be done within council's planning controls," she said.

Cr Porteous said a number of other Sydney councils had called Leichhardt's legal team to congratulate them on the win and ask how they pulled it off.