The entire, 800-strong police tactical unit will be on standby for tomorrow's vote on funding for the multibillion-dollar express railway project, with opponents threatening to surround the Legislative Council building with 10,000 protesters.
The last time the entire police tactical unit was placed on standby was during protests by Korean farmers at the World Trade Organisation meeting in 2005.
Police negotiation experts will also be on standby for tomorrow's showdown in case tempers start to fray.
The negotiators have previously only been deployed for major public events such as the WTO meeting and the Olympic equestrian competition in 2008.
Police are concerned about the impact of the protest on traffic and public order in Central, especially since 800 people have joined a Facebook group to chat about their 'readiness for commotion and bloodshed' during the protest.
The protest's organiser - an alliance of the Justice and Peace Commission of the Hong Kong Catholic Diocese and a group of youngsters who call themselves the Post-80s Anti-Express Railway Group - said opinions would be expressed in a peaceful and rational manner.
Organiser Huck Yuen, who denied any links with the Facebook chat group, said: 'A lot of people and groups are planning their own actions right now.
'We will be peaceful and show restraint but there is no way we can know or prevent actions others may take.'
More than 100 police from the quick reaction team and uniformed officers from Central district will be deployed to manage the crowd.
Supporters and opponents of the HK$66.9 billion high-speed rail link to Guangzhou have been lobbying support since November.
A survey of 1,018 people by the University of Hong Kong found that 45 per cent opposed the project or demanded its suspension, almost triple the 16 per cent in a similar survey in May.
Only 47 per cent of respondents supported the project, down from more than 80 per cent in May.
Nearly 60 per cent said they had little knowledge of the project.
Pan-democrat lawmakers, meanwhile, are finalising tactics to delay tomorrow's vote.
Albert Chan Wai-yip, of the League of Social Democrats, said he and his two colleagues - Leung Kwok-hung and Wong Yuk-man - would each propose a motion during the six-hour meeting, such as urging the government to reconsider moving Tsoi Yuen village to another place.
The Transport and Housing Bureau has already ruled out that option, saying that rebuilding the village would recognise the legality of unauthorised squatter huts and cause upheaval to existing land policy.
Professional Commons - a group of experts closely connected to the Civic Party - is demanding time to talk about its alternative proposal during the meeting.
'The taxpayers are paying an unnecessary HK$13.4 billion if the project begins now because the building tender works price is rising in light of the many infrastructure projects on the go,' group spokesman Albert Lai Kwong-tak said.
Lawmakers had suggested Lai speak at a Legco rail subcommittee meeting instead but he refused that offer.
Legco will hold a meeting today to decide if the group should be allowed to address tomorrow's meeting.
More than half of lawmakers have expressed support for the project. This means that delaying funding is all the pan-democrat camp can do to prevent construction of the link, which would hook up to the national high-speed rail network by 2015.
But Chan said they would fight until the last minute and would walk out of the meeting in protest when the council voted on the government's HK$2 billion compensation package for Tsoi Yuen Tsuen land owners and residents.
The Finance Committee can conduct another special meeting to continue deliberation of the project's funding if tomorrow's meeting fails to yield an outcome.
Two sides of the track
- A group of post-50 engineering, construction, planning, finance and legal professionals
City?s status as world-class metropolis at stake
- Business Community Joint Conference (67 associations of small and medium-sized enterprises)
Line to greatly benefit Hongkongers working on mainland and more than recoup its cost
- Four major business chambers
Quicker journeys; boosts city?s economy; creates jobs
- Construction Industry Employers General Union
We have to make sure our children have enough food to eat
- Institute of Engineers
Judging it on cost-effectiveness alone is simplistic
- Professional Commons
Too costly, affects too many communities, public consultation lacking
- Tsoi Yuen Tsuen residents
Destroying our village will be like killing us
- Post-80s Anti-Express Railway Group
Lawmakers close to government have veto over major projects and political reform; rejecting project can change this
- Government Front-line Staff Union
Money can be better spent on other projects
- Tai Kok Tsui residents
Safety risk to old buildings, and they can?t be redeveloped
The project in numbers