Top heritage adviser Bernard Chan dramatically quit yesterday after being accused of colluding with officials over Government Hill.
At least three other members of the Antiquities Advisory Board also indicated they would resign as development secretary Carrie Lam Cheng Yuet-ngor faced criticism for allegedly bypassing the heritage process.
Chan's resignation came after Lam announced last Thursday that the former government headquarters would be demolished to make way for a 32-storey office block.
Hours later, Chan used his deciding vote to make the board recommend a grade II status for the 52-year-old west wing for a public consultation. His move followed a stalemate among board members, with eight voting for grade I, eight for grade II and four for grade III.
A grade II building is not generally safe from demolition, while a grade I building may be protected if it is then declared a monument.
Critics say Lam should not have announced the demolition plan for the west wing before the board had met. She said Chan 'supported' the announcement, which would 'clear any political disturbances for the AAB'.
Chan admitted that Lam's remarks would invite speculation that he had colluded with her, but said she could have clarified his view. 'I couldn't control the manner in which [Lam] announced the plan,' he said.
He was attacked by the Government Hill Concern Group for agreeing with the minister, despite a warning by an international body that advises the United Nations on heritage sites. He added: '[My presence] will continue to be an excuse for people to attack the AAB's work ... I don't want the discussions to dwell on whether I was biased for the government. My resignation will stop it.'
Although Lam and 18 out of 22 board members wrote to Chan asking him to stay, he said he would remain only until a new chairman was appointed. He said he would not vote in the next meeting, when the board will decide on a final historical grading for the west wing after a month-long public consultation.
Lam said she felt 'deeply upset' that conservationists had made unreasonable accusations against Chan. 'I fear that this would deter any passionate and professional personalities, and the government and the public will not be able to heed their views in future conservation work.'
Following Chan's resignation, Andrew Lam Siu-lo, Lau Chi-pang and Lee Ho-yin indicated they would also quit in support of the chairman, maintaining that the board did not make a mistake.
Members including Ko Tim-keung, Tony Lam Chung-wai and Ho Pui-yin, praised Chan for raising the board's transparency and said officials should be blamed instead.
Ho said: 'The government's announcement made me unable to decide on a grading independently and calmly ... It made me feel the board does not have influence.'
Chung Kim-wah, a public policy researcher at Polytechnic University, said Lam's tough stance raised concerns about the impact she would have in Leung's administration.