Students plan an overnight sit-in after today's annual march for democracy as a rehearsal for Occupy Central's planned blockage of the city's business heart. The Federation of Students and Scholarism announced their plan yesterday as police said they would assign 4,000 officers to keep order during the march. It will be the largest deployment since the Korean farmers' violent protest at the World Trade Organisation's ministerial conference in 2005. Businesses and banks, meanwhile, say contingency plans are ready and they will step up security measures if necessary. A big turnout is expected today amid unrest over political issues including Beijing's white paper affirming its "comprehensive jurisdiction" over Hong Kong and following Occupy Central's unofficial referendum on universal suffrage that drew almost 800,000 voters. [Marching] is not enough. We have to upgrade it to a civil disobedience movement ALEX CHOW The State Council's Hong Kong and Macau Affairs Office labelled the vote unlawful, while the central government's liaison office dismissed it as a "farce". The students aim to draw 2,500 people for their sit-ins in Chater Road and outside the chief executive's office in Admiralty, to end at 8am tomorrow. "We have gathered enough public opinion on public nomination. Now it's time to act," student federation secretary-general Alex Chow Yong-kang said. "It's not enough to repeat the march and the assembly every year. We have to upgrade it to a civil disobedience movement." 'Don't be kidnapped by radical opposition': State media warns Hongkongers against July 1 march He spoke a day after the referendum ended with the proposal put forward by the federation and Scholarism coming second, behind that of the Alliance For True Democracy. The Occupy movement plans to block streets in Central if the government does not deliver a blueprint for the 2017 chief executive election that guarantees voters a genuine choice. The students said they differed from key Occupy figures, who have said the government must be given time to respond to the poll results. "If we hold on until officials have finalised their decisions, it will be too late," Chow said. Scholarism convenor Joshua Wong Chi-fung said members were prepared to be arrested but would avoid clashes with the police to keep the protest peaceful. Occupy founder Benny Tai Yiu-ting said he respected the students' decision. Organisers hope more than 500,000 will turn up for today's march, with a theme of universal suffrage. That would make it the biggest July 1 since 2003, when half a million took to the streets over plans to introduce an anti-subversion law. As financial institutions in Central prepared to deal with any effects on their business, the Monetary Authority said it did not want to see normal bank operations disrupted. It said that according usual practice, banks had been instructed to prepare a "business continuity" plan. The Securities and Futures Commission has a similar plan. HSBC would not comment directly on the students' actions. A spokeswoman said the bank would step up security measures if necessary. These are understood to include allowing staff to work from home or other offices. Last night, hundreds of metal barricades were in place around Chater Garden, while the front gate of HSBC headquarters was down. A police source said if Chater Road was blocked by protesters, officers would issue a warning. If this was ignored, they would lift protesters and remove them. The Police College in Wong Chuk Hang will be used for the first time as a detention centre if more than 100 protesters are arrested. Qi Pengfei, vice-chairman of the Chinese Association of Hong Kong and Macau Studies, said the room for moderate pan-democrats to engage in dialogue with the central government would further shrink if there was a massive turnout today.