Ironically, the first major handover anniversary protest in 2003 was triggered by the government's attempt to force through the controversial Article 23 legislation, which criminalises adverse actions against the central government.

In the following days, the legislation was shelved and the security secretary at the time, Regina Ip Lau Suk-yee, quit in the wake of the huge turnout, estimated at half a million by the Civil Human Rights Front, the protest organiser, and 350,000 by the police.

Furthermore, the popularity rating of the chief executive at that time, Tung Chee-hwa, nosedived to a record low of 36.2 points. Tung resigned his position in March 2005.

Last year's handover anniversary protest was among the main contributing factors that led the government to amend legislation for a replacement mechanism in Legislative Council elections.

Dr Dixon Sing Ming, a political scientist at the Hong Kong University of Science and Technology, said these 'achievements' had awakened many Hongkongers, who formerly thought they had little say in politics.

'The protests have reduced people's sense that they lack political clout and increased their sense of political advocacy,' he said.

'Every year, the handover rally serves as a chance for members of the public, non-governmental organisations and political parties to express themselves and to vent their anger. People started to realise that mass mobilisation could increase their bargaining power.'

Dr Francis Lee Lap-fung, associate professor at the Chinese University's School of Journalism and Communication, said there had not been any significant rise in the number of protests over the past 12 years - around 1,000 a year. But he said it was not the number that mattered, but the variety of messages.

'Over the past 10 years, the backgrounds of rally organisers have become more diversified,' said Lee, who has been researching the city's pro-democracy movement. 'Even some pro-government groups would use rallies as a tool to show support for particular policies.'

Eric Lai Yan-ho, of the Civil Human Rights Front, said in the past only individual political parties or groups would organise rallies. 'But after the 2003 march, more Hongkongers would assemble and take to the streets,' Lai said.

Hung Hiu-han, of Art Citizens, a group which participated in last year's march, said the rally made it easier for them to gather their members. 'They think they're going to the rally anyway, so it's easier to get everyone together,' Hung said.

Chinese University's Lee said the 2003 march helped locals realise that protests were not necessarily chaotic or violent, and that an increase in the variety of rallies could be a sign of a maturing society. 'They have become more comfortable with demonstrations after seeing the peaceful march of 400,000 people,' Lee said.

Every year the march has been organised with different themes. While some of the issues have been addressed, many have not, including the wide wealth gap and developers' economic and political influence. Protesters also deem as unsatisfactory the apparent collusion between the government and tycoons and the progress of political reform.

Lee said the lack of progress in some areas should not be seen as the annual march losing its clout. 'Whether a protest has an immediate positive effect depends on a lot of factors, such as how concrete the demand is,' he said. 'Even if there's no instantaneous result, protesters are exerting a great deal of pressure on the government to respond.'

And it was unlikely that protesters would be discouraged, he said. 'As long as they can recall some landmark achievements, they have the incentive to carry on.' Over the years, the number of marchers has fluctuated, plunging to the lowest point in 2005, following Tung Chee-hwa's resignation that March. The organisers said there were 21,000 participants that year, while the police placed the figure at 17,000.

Last year's turnout was the biggest since 2004, with the organiser saying there were 218,000 people and the police saying 54,000.

From 2009, some protesters began staying behind after the main rally and continued their demonstrations until the early hours of the next day. Some of them were removed and then arrested.

Clashes between police and protesters have become more frequent in various rallies in recent years. After last year's main rally, scuffles broke out between police and about 200 protesters at the Cheung Kong Center in Queen's Road and in Connaught Road Central.

Political scientist Dixon Sing said it showed some young people were 'starting to get fed up with the rituals of protests' and chose to vent their anger with other symbolic actions. 'It's still evolving. It could end up that they are just changing from one ritual to another, but they are still trying out different ways,' Sing said.

Art Citizens's Hung, who was arrested after staying behind and blocked Counnaught Road Central last year, said it was important to let the public get used to different ways of protesting.

'We need to think out of the box. Even after Tung stepped down, our lives haven't improved a lot, so it's not only about pulling someone down, but also how we could influence other people to do a little more in their daily lives, instead of only participating in the rally once a year,' she said.

'I'm not saying that the rally has no use, but if, let's say, one-third of the participants took an extra step to fight for justice in their daily lives and in their jobs, there can be a big difference.'