Cheng also convicted Hui, who read content on the phone and sent five files to his own email account, of obtaining access to a computer with dishonest intent.

The magistrate adjourned the case to June 10, seeking a report to study whether community service was suitable.

“The possibility of an immediate custodial sentence exists,” he said.

The incident took place in the Legislative Council last year during a debate of a controversial co-location plan, which would see mainland Chinese laws applied in Hong Kong for the first time.

When the government sent officers to monitor lawmakers in the legislature complex, Hui argued the move infringed their privacy and compared the officers to “paparazzi”.

Testifying during his trial, Hui also cited fears the information could be passed to mainland Chinese officials in Hong Kong.

Cheng on Monday ruled there was no evidence Leung and the government had infringed lawmakers’ privacy. Hui’s complaint to the Privacy Commission had yielded no response, he said.

“The court disagrees the scrutinising squad interfered with the operation of the Legislative Council,” Cheng added.

Hui made his own mitigation speech, urging Cheng to look at it from his perspective.

“One doesn’t just look at whether it is lawful or unlawful … One also has to consider whether it is just,” he said, insisting the government had gone beyond the law to trample the authority of the legislature.

On the day, Hui approached Leung at the lift lobby, before snatching her phone. He ran to a men’s toilet where he sent five files from the government phone to his own email account.

Cheng found that Leung had suffered fear and anxiety as a result of the assault. He said Hui had neglected the ensuing consequences and only cared about snatching a phone he thought would expose evidence of a privacy infringement.

Hui conceded on Monday his conduct had “exceeded the constraint of society”, and apologised to Leung.

Hui’s barrister Joe Chan Wai-yin urged Cheng to consider community service as punishment.

Cheng said the charge of obtaining access to a computer with dishonest intent was serious, even though Hui had accessed public information documents.

Hui faces up to a year in jail for the assault charge, and six months and a HK$1,000 fine for obstructing a public officer. Obtaining access to a computer with a view to dishonest gain carries a maximum sentence of five years in jail.

He would face losing his seat if he was jailed for more than a month and an impeachment motion was supported by a two-thirds majority of Legco.

His supporters filled the courtroom, among them party colleagues and lawmakers, James To Kun-sun, Roy Kwong Chun-yu and Lam Cheuk-ting.

“Shame on political persecution. Shame on the administrative arm for interfering with the legislature,” one shouted from the public gallery as Hui was found guilty.

Democratic Party chairman Wu Chi-wai said it is up to the party's disciplinary committee to follow up on the incident.

“As for Ted Hui's seat [in Legco], it is up to voters to decide,” Wu said.

The party said earlier that Hui's case was being followed by its disciplinary committee, and that it will only take further action when more evidence comes to light, or when the court makes a ruling.

Unionist lawmaker Alice Mak Mei-kuen, who chairs the closed-door investigation committee in respect of the motion to censure Hui, said she would seek to arrange another committee meeting before the summer recess.

Mak said the court ruling would not affect the committee's work.

“The trial and the judgment might provide us more evidence and references but we will have to check whether we can use these materials, along with others such as media reports, and how we may use them,” Mak said.

A spokesman from Transport and Housing Bureau said: “As judicial proceedings on the case are underway, it is not appropriate for this Bureau to provide any comments.”

Additional reporting by Su Xinqi and Sum Lok-kei