It was the biggest protest in Hong Kong since 1.2 million people hit the streets in support of the Tiananmen Square pro-democracy movement in 1989.

Referring to the overwhelming response at the end of the seven-hour protest, front spokesman Lee Cheuk-yan said: 'The figure is really no longer important. We have made history today. I think Mr Tung should seriously look at this.'

The group demanded an immediate dialogue with Mr Tung and urged him to shelve the controversial national security legislation and speed up democratic development.

It threatened to mobilise the public to besiege the Legislative Council building on July 9, when the national security legislation is put to a vote. The bill is aimed at outlawing offences such as subversion, treason and succession.

Mr Tung said in a statement that he was 'very concerned' about the mass protest and that he understood the people's aspirations. He said the government and the public shared the same position on the importance of rights and freedom.

'We shall continue to take active steps to maintain and safeguard rights and freedoms and develop democracy in a gradual and orderly manner according to the blueprint laid down in the Basic Law,' he said.

He repeated that it was Hong Kong's constitutional duty to enact the legislation.

The chief executive said the government understood the public was experiencing hardship amid economic restructuring and was taking measures to ease unemployment. He pledged to strengthen communication with the public.

Mr Tung said he hoped the community would build on the spirit of solidarity developed in the fight against Sars and work together to relaunch Hong Kong and revitalise the economy.

Despite the massive turnout, the Democratic Alliance for Betterment of Hong Kong and the Liberal Party said they did not plan to back down on their support for the national security legislation.

The response was so overwhelming that tens of thousands of people were still pouring in to Victoria Park hours after the first batch arrived in Central at 4.15pm. The last batch of protesters arrived at Central Government Offices shortly after 9pm, six hours after protesters started leaving Victoria Park.

Brandishing anti-Tung placards and chanting slogans against the government, protesters, dressed mostly in black, braved scorching heat to vent their anger. They carried effigies of Mr Tung and Secretary for Security Regina Ip Lau Suk-yee as they walked from Causeway Bay to Central.

Police were forced to open more thoroughfares for the protest as tens of thousands of people were still waiting to move out of the park late in the afternoon.

Premier Wen Jiabao, who left hours before the march began, told principal officials not to disappoint the public.

'Understanding, trust and support are most important in the current situation. You have a great mission ahead. You should not disappoint the Hong Kong public and the Chinese people,' he said.

Asked why he did not stay to address the protesters' concerns, Mr Wen said: 'My three-day mission is over. My job to bring warmth and hope to Hong Kong has finished. I have said what I have to say.'

In his first direct comments on Article 23, Mr Wen said: 'Article 23 will not affect Hong Kong people, including reporters, from enjoying their various rights and freedoms under the law.'

Commenting on the march, Secretary for Home Affairs Patrick Ho Chi-ping admitted that the government had to improve its responses to public sentiment. Dr Ho said: 'Premier Wen has given me much insight personally. We still have a great deal to learn about how to get closer to the public.'

City University political commentator Ivan Choy Chi-keung said the march had shown that Mr Tung was facing a governance crisis.

'Mr Tung should shelve the legislation indefinitely and remove Regina Ip to appease public outrage,' he said.