He reassured supporters: "Don't treat me as a democracy traitor. I am still a friend of democracy. I just like to jump out of the framework to look at things from a different viewpoint."

Tong's withdrawal from the political party he co-founded and his resignation from the Legislative Council are the latest testament to the growing split within the pan-democratic camp, with moderates and hardliners increasingly unable to agree on how to deal with Beijing and the fight for democracy.

While moderates may appear pragmatic, the more vehement pan-democrats see them as being too timid to take a stand, said Dr Chung Kim-wah, an assistant professor of public policy at Polytechnic University. He described the sentiment within the camp as, "you are either with me or you are my enemy".

Because of that, more moderate pan-democrats were likely to follow Tong's lead and split from the loose coalition, said Professor Sonny Lo Shiu-hing, head of social sciences at the Hong Kong Institute of Education.

Those moderates, he said, were likely to run as independent candidates in next year's legislative election when "the voters will tell them if their ideas are welcome or not".

Chung said public sentiment had changed. "The people seem to be getting impatient and want quick results, though sometimes the means they choose to employ may not be altogether workable," he said, citing last year's Occupy protests. "On the contrary, the moderates like to seek compromise to arrive at a solution that provides a workable outcome."

Tong, founder of a public policy think tank called Path to Democracy with moderate pan-democrats and academics, hopes to explore "a third road" for political development and improving relations with Beijing.

His stance contrasts with that of the Civic Party, whose leader Alan Leong Kah-kit favours a more hardline approach towards Beijing.

Tong's withdrawal came weeks after news that veteran Democrat Nelson Wong Sing-chi could be thrown out of the Democratic Party for expressing "alternative" views about constitutional development. Wong, a founding member of the party, was earlier kicked off its central committee after voicing support for the government's electoral reform package.

"I just tried to raise an alternative view. The bad thing now is that the pan-democrats are fighting among one another for political gain at the expense of Hong Kong's interests," Wong said.

"The problem we have is more than just supporting the government's political reform or not. It seems Hong Kong's democracy force is crumbling because of a loss of direction."

Political scientist Dr James Sung Lap-kung of City University said the lack of a strong leader like Szeto Wah in the pan-democratic camp was to blame for the "directionless democracy drift".

Szeto, who died of cancer in 2011, was widely regarded as a spiritual leader of the camp.

"The situation could have been better if Szeto was still here to head the camp," Sung said. "He led social movements since the 1970s and knew the Communist Party and understood how it deals with opponents."

Democratic Party chairwoman Emily Lau Wai-hing "does not seem to be able to control her men", he said. Leong "seems not to be able to provide a direction either, except for saying no to whatever policies are proposed by the government". Even former chief secretary Anson Chan Fang On-sang and Democratic Party co-founder Martin Lee Chu-ming are "yesterday's people", Sung said.

City University political scientist Dr Cheung Chor-yung, a member of Tong's think tank, shared similar views, but added: "The younger generation's refusal to recognise the older members' ways of fighting for democracy is also contributing to the pan-democrats' split.

"Some think resorting to violent or radical protests can force Beijing to back down, while others think Hong Kong can simply become independent.

"These naive ideas surely offer no way out. Instead, the young groups only further weaken our democracy movement.

"I am not saying the pan-democracy camp is tipping into a kind of civil war. But the split will likely complicate the prospects of the pan-democratic parties in the district council elections this year and in next year's legislative poll."

Over the past year, pan-democrats have been in the news as much for internal disputes as their fight for democracy.

Ahead of the Occupy campaign, the Democratic Party quit the Alliance for True Democracy - a grouping that consisted of 26 out of 27 pan-democratic lawmakers - because of a row with the People Power party and other radicals in the alliance over the approach to democracy.

The subsequent Occupy campaign that started last September in protest against Beijing's framework for the 2017 chief executive election demonstrated that mainstream pan-democrats had lost the ability to lead and provide direction, Cheung said.

It was the Federation of Students and Scholarism which emerged to helm the 79-day protest after leading young activists who tried to storm the government headquarters in Admiralty.

Things got even worse after the protests. Even the federation fell apart as it was hit by a wave of disaffiliation campaigns by member unions at universities.

The reform package was voted down in the legislature last week after opposition by all the pan-democrat lawmakers. They now risk being punished by moderate voters who think Beijing's offer is better than nothing.

"Beijing, perhaps, will be the sole winner from divisions within the pan-democratic camp", Cheung said.

A history of turmoil in Hong Kong's opposition pan-democratic camp

Some younger members of the Democratic Party, unhappy with the leadership's election strategy, quit to join another pro-democracy group called The Frontier.

Pro-democracy legislators Mandy Tam Heung-man, Dr Kwok Ka-ki and Joseph Lee Kok-long won't support fellow pan-democrat Fernando Cheung Chiu-hung's motion for a referendum on universal suffrage.

A group of pan-democrats form the League of Social Democrats to represent grassroots and working-class interests.

• The Civic Party, regarded as a major competitor to the Democratic Party, is formed.

The Democratic Party declines to support a "de facto referendum" plan initiated by the Civic Party and the League of Social Democrats.

The Democratic Party supports the government's political reform package after behind-closed-doors talks with officials from Beijing's liaison office. The package is passed thanks to their votes.

• People Voters is set up to mobilise those unhappy with the Democrats' support of the government package.
• So-called Young Turks of the Democratic Party, unhappy with its strategy, quit to form the NeoDemocrats.

Wong Yuk-man and Albert Chan Wai-yip quit the League of Social Democrats and join People Voters, which later evolves into People Power.

The Democratic Party quits the Alliance for True Democracy over criticism of its support for the 2010 reforms.

Democrat Albert Ho Chun-yan announces plans to resign from the legislature to trigger a de facto referendum on universal suffrage.

• Democrat Nelson Wong Sing-chi calls on the pan-democrats to support the government political reform package. He is removed from the party's central committee and suspended from the party.
• Civic Party legislator Ronny Tong Ka-wah announces plans to convene a platform to consolidate "moderate power" in Hong Kong politics.
• The Federation of Students, which led the Occupy protest, is hit by a wave of disaffiliation as students from the University of Hong Kong, Polytechnic University, Baptist University and City University vote for their student unions to disaffiliate from the group.
• In order to focus more on local issues, The federation announces it will not join the June 4 vigil organised by the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, of which the federation is a founding member.
• Ronny Tong quits the Civic Party and announces he is resigning as a legislator