'In June I will be 70 - it is time to get some new blood. No one person is indispensable,' Mr Lee, who was a founding member of the city's Democratic Party, said by phone.

He will step down from the city's Legislative Council when his term ends in July, he said.

Mr Lee has been at the forefront of the movement to introduce universal suffrage in Hong Kong, which was transferred back to China in 1997 from colonial power Britain with a guarantee democracy would be introduced.

However, the introduction of voting rights has faced delays from Beijing, which late last year said the city's chief executive could be fully elected in 2017 at the earliest.

Mr Lee said the failure to ensure universal suffrage in Hong Kong was his biggest regret.

'But I will fight until my body has no breath left,' he said when asked if he would continue his campaigning after leaving his seat.

'I think it is ridiculous to have to wait for 10 years before being given democracy.' Hong Kong only selects 30 of its 60 legislators by universal suffrage.

The remainder, and the city's chief executive, are chosen by around 800 mainly pro-Beijing elites, including business and industry representatives.

Mr Lee, a practising lawyer, said his proudest achievement was ensuring that the territory's legal system had maintained its independence from the mainland since 1997.

'The principle reason I entered politics - I wanted to preserve the rule of law. So far it is still OK,' he said.

British consul general Stephen Bradley told the South China Morning Post Lee was 'a towering figure' in Hong Kong politics.

Mr Lee was selected by Beijing as one of the first figures to prepare to run Hong Kong after 1997.

He was part of the team that drafted the Basic Law document aimed at guiding the city's transfer from British to Chinese rule, but he resigned in protest at the crackdown by Chinese authorities on a 1989 protest in Tiananmen Square.

The bloody crackdown in Beijing left hundreds, possibly thousands of people dead.

Mr Lee has become a regular target for pro-Beijing loyalists, and has only been allowed into the mainland once since 1989.

He faced a barrage of criticism last October when pro-Beijing politicians and newspapers attacked him for an editorial he wrote in the Wall Street Journal calling for world leaders to press China on human rights ahead of this summer's Olympics.

One editorial called him a 'crazy traitor', while leading pro-Beijing politician Tam Yiu-ching said he was advocating outside interference in China's internal affairs. -- AFP