Flanked by four other senior party members, Wu bowed and said: “He bullied and offended the female officer, seriously tarnished the party’s reputation. His act was extremely inappropriate, and fell short of public expectations.”

Hui’s suspension means he cannot speak on behalf of the party on any policy issues or during Legco debates. The party has in recent years positioned itself as a moderate voice in the pan-democratic camp, especially with the rise of radical, localist and pro-independence groups.

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Former Democratic Party chairwoman Emily Lau Wai-hing, who rarely criticises party colleagues, was among those who slammed Hui, saying she found his actions “absolutely shocking, outrageous and disappointing”.

She made clear she spoke as “an ordinary member of the party”, but stated: “I think it is unsuitable for him to be a lawmaker and stay in the party.”

Another former party chairman, Albert Ho Chun-yan said: “We think his previous apology was not sincere enough … I hope he could thoroughly reflect [on his behaviour].”

Lam called Hui’s actions “barbaric” and confirmed the female employee was in tears when she told her colleague about what had happened.

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“It was Hui’s personal behaviour, I believe that he will bear personal responsibility,” Lam said, adding that Hui should “deeply reflect” on whether he is still fit to stay in office.

The pro-government camp will on Friday decide whether to move a motion to censure Hui. This would trigger an investigation, which could take months, after which the motion would be put to a vote. If two-thirds of lawmakers agree, Hui will be booted out of Legco.

Legal experts said Hui, who is also under police investigation, could have committed six criminal offences.

Hui was contrite. He also sent an open letter to the woman, who had been trying to marshal lawmakers into a meeting to discuss a government bill when the incident happened, saying he had no “defence for my offence to you”.

He bowed before press cameras on Thursday evening and tears welled up in his eyes as he spoke.

“I’ve been very wrong in the incident, the behaviour was extremely inappropriate … and disappointed the public, so I’ll apologise to the official and the public.”

“The incident caused troubles to my friends, but the mistake was mine … I will go back and deeply reflect on it,” he said.

Hui, who has a law degree, said earlier he hoped the civil servant would understand he intended to expose how the government had breached the privacy ordinance and improperly intervened in the affairs of Legco.

Legco President Andrew Leung Kwan-yuen said there would be a closed-door screening of CCTV footage of the incident on Friday afternoon for all lawmakers.

The clip could be made public upon approval by all the parties involved, including police, who are investigating the case, he said.

According to sources who saw the footage, Hui saw the Security Bureau employee at the lift lobby and went to see what she was doing.

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He grabbed a sheet of paper she had – a list of lawmakers with their photos – and pointed at her phone. She put the phone behind her back and the two struggled. After disappearing into a blind spot, Hui reappeared with the phone and dashed to the toilet, dropping the sheet of paper on the way. The officer gave chase but could not catch him. He later passed the phone to another official.

New People’s Party chairwoman Regina Ip Lau Suk-yee said the pro-establishment camp would make a final decision on moving the censure motion after viewing the clip.

“He has set a very bad precedent. If we do not censure him, the impact [for Legco] would be very serious,” she said.

The incident also triggered responses on how to take lawmakers to task for improper conduct.

The Legco Commission – which handles administrative matters – issued a “strong” condemnation letter to Hui, while lawmakers called for tougher penalties for those who misbehaved and a review of whether more security cameras were needed to cover blind spots.

Paul Tse Wai-chun, chairman of Legco’s committee on rules of procedure, said there should be better ways of disciplining lawmakers for misconduct, including fines and duty suspensions. Currently, there were “two extremes”.

“On the one hand, we have the toothless warning letter and on the other hand, removing a lawmaker from office if we pass a censure motion.”

Additional reporting by Sum Lok-kei