Two decades ago, the British government believed handing over Hong Kong to Chinese sovereignty would give it greater influence and commercial opportunities in China, according to newly released cabinet papers.
And the prime minister at that time, the late Margaret Thatcher, was optimistic about Sino-British relations as she announced "a breakthrough" in August 1984 in negotiations on the handover.
The papers were made public this month under a 20-year rule demanding the release of classified British files.
According to the documents, Geoffrey Howe, then secretary of state for Foreign and Commonwealth Affairs, told Thatcher that Hong Kong was the most substantial and important matter on which the Chinese had engaged with any foreign government, particularly in the West.
"The change in China's economic attitudes provided important opportunities, in particular to the United Kingdom, which would be working closely with the Chinese during the transitional period in Hong Kong before 1997," Howe told Thatcher, according to the documents.
"The United Kingdom would have a chance to exert influence on Chinese thinking on wider issues as well, at a time when China's fear of the Soviet Union remained obsessive but when, equally, the Chinese government did not wish to be associated too closely with the United States."
There could also be significant commercial and diplomatic opportunities for Britain, according to the papers.
Thatcher concluded that Britain had won China's trust on the issue, after it signalled it was prepared to accept an agreement "to a considerable extent on British terms". She believed this would offer important opportunities for Britain in the future.
Veteran China watcher Johnny Lau Yui-siu said the documents again showed that Britain did not have Hong Kong's best interests at heart during the handover negotiations.
Howe's stance was to push Britain's interests in the talks, but he had to be seen to be accommodating China's demands, Lau said.
"As a result, from what we can see in Hong Kong today, the pace of development in terms of democracy has dragged," he said.
The Sino-British Joint Declaration was signed by China's premier at the time, Zhao Ziyang , and Thatcher in Beijing on December 19, 1984.
Ming Pao Daily reported yesterday on another declassified document from 1984, which reveals that the British government was considering allowing Hongkongers to elect their own governors as one of four constitutional reform plans being discussed.
Another plan was to keep the appointed governor but to allow locals to elect a chief minister.
But Britain did not make these suggestions to China amid fears that they could hamper talks on Hong Kong's future, according to the newspaper report.