Notable faces included four recently disqualified lawmakers, who lost their seats in a court battle against the previous administration over the validity of their oaths.

The campaign was launched on the eve of a special meeting in the Legislative Council, where top government officials were due to face lawmakers for the first time since the unveiling of joint border clearance arrangements for the HK$84.4 billion Guangzhou-Shenzhen-Hong Kong Express Rail Link.

Civic Party lawmaker Tanya Chan, the group’s interim convenor, said the coming three months would be crucial.

“We know a resolution may be tabled to Legco by November ... if we cannot win public support, it will be very difficult to press the government to listen,” she said, referring to the final legislation stage required for the arrangement to take effect.

The group did not specify if it would concede defeat if it failed to collect 300,000 signatures by October.

The idea to sway public opinion against government policy through a mass opposition campaign has been used successfully in the past, most notably in the anti-national education protests of 2012, which were spearheaded by students’ and parents’ bodies who feared the curriculum would brainwash youngsters.

Opposition quickly snowballed into a rowdy sit-in outside government headquarters, prompting authorities to eventually back down and set aside the curriculum indefinitely.

Hong Kong’s pan-democrats are on the wrong track with express rail border checks row

Students are on board again in the latest campaign, with 12 tertiary student bodies signing the petition on Wednesday.

Hong Kong University Students’ Union president Wong Ching-tak said they felt it was the right time to take action.

“The Chinese government is intervening in all aspects of our lives, [while] disregarding our opinions,” he explained.

On a two-day visit to Singapore, the chief executive said her administration would continue to address any concerns about the co-location arrangement.

But Lam, who was in the city for her first international visit, added: “I just do not see any alternative to doing this co-location in order to reap the huge economic and social benefits arising from [the rail link].”

She also called on Hongkongers to study the arrangement “objectively, rationally and practically”.

Tensions were already simmering before the campaign took off, starting with the pan-democrats boycotting a visit to the West Kowloon terminus under construction and Shek Kong depot on Wednesday. Only about a dozen pro-establishment legislators showed up.

The pan-democratic bloc boycotted the tour as it had demanded that three officials responsible for the co-location plan – Secretary for Justice Rimsky Yuen Kwok-keung, Secretary for Transport and Housing Frank Chan Fan and Secretary for Security John Lee Ka-chiu – should also be present at the site visit.

Lam described the boycott as “strange and incomprehensible”.

“The three officials are already scheduled to attend the special housing committee meeting tomorrow [Thursday] to address [lawmakers’] concerns,” she said.

Asked if another tour would be arranged for the democrats, MTR chairman Frederick Ma Si-hang said he would consider such a request.

But Ben Chan Han-pan of the pro-Beijing DAB party slammed it as a waste of manpower and taxpayers’ money.

Who’s in the group?

The “Co-location” Concern Group is made up of 48 groups and 45 individuals.

Individuals:

*Four disqualified lawmakers: Edward Yiu Chung-yim, Nathan Law Kwun-chung, Eddie Chu Hoi-dick and Lau Siu-lai.

*Non-establishment lawmakers: Tanya Chan, Alvin Yeung Ngok-kiu, Claudia Mo, Fernando Cheung Chiu-hung, Charles Mok, Jeremy Tam, Dennis Kwok

*Others: Margaret Ng Ngoi-yee, Benny Tai Yiu-ting, Alan Leong Kah-kit

Groups:

*Political groups: Civil Human Rights Front, League in Defence of Hong Kong’s Freedoms, Power for Democracy, CoVision16

*13 tertiary education student unions: Student Fight For Democracy, and other groups from the University of Hong Kong, Chinese University, the Open University, the Education University, City University, Baptist University

*Legal groups: Progressive Lawyers Group

*Welfare groups: Reclaiming Social Work Movement

*Localist groups: Liber Research Community