Secret details of deals struck between Britain and China before the handover should be made public to shed light on controversial issues such as universal suffrage, a prominent lawyer says.
Senior Counsel Alan Hoo called on London to release records of the Sino-British Joint Liaison Group's closed-door meetings in 1988 and 1989.
His call came in response to a reference by Britain's Foreign Office to Article 45 of the Basic Law on universal suffrage in its most recent six-monthly report to parliament on Hong Kong affairs.
"What they must do, in the interests of the people of Hong Kong, is to make full and frank disclosure of all these agreements and accords," said Hoo, who also chairs the Basic Law Institute, a non-governmental organisation.
"These were crucial years. The JLG documents will contain all accords on important matters such as the method of selecting the chief executive which was subsequently incorporated into Article 45 of the Basic Law."
Hoo told the South China Morning Post details of meetings would reveal that it was the Chinese government that introduced the idea of universal suffrage and Britain's position on these issues at the time. "All these things, whether you agree with them or not, should be made known to the public so that we can have a meaningful debate," he said.
His remarks come amid debate about the "one country, two systems" concept underlying Hong Kong's return to China.
This week, Beijing released a white paper setting out its position on Hong Kong. Hoo said the paper, one of 89 issued since 1991, was primarily published for the international community on matters of Chinese national policy, especially sovereignty.
There has also been controversy over the meaning of Article 45 as the government prepares a package of reforms for the election of the chief executive by universal suffrage in 2017.
The Joint Liaison Group first met in 1985 to discuss Hong Kong's return to China. Records of these meetings are not due to be declassified by the British government until 30 years after their creation.
Hoo's comments follow a warning from Beijing's top foreign ministry representative in Hong Kong, Song Zhe, that Britain should not interfere with Hong Kong's constitutional development. The warning was sparked by remarks attributed to British consul-general Caroline Wilson last month, saying the international business community in the city was deeply concerned about electoral reform.
Hoo said further information would help Hong Kong courts interpret the Basic Law and avoid constitutional controversies over matters such as right of abode.
Simon Young Ngai-man, a University of Hong Kong law professor, said he was sceptical about how much light the Joint Liaison Group documents would shed on universal suffrage but added it would be interesting to see the genesis of the idea.
"Who initiated that idea and where has it come from? That would be interesting to research," he said.
The British government said it was not able to comment.