This photo dated June 26, 2017 shows Chinese Ambassador to the United Kingdom Liu Xiaoming giving a speech at an event marking Hong Kong's return to China and the 20th anniversary of the establishment of the HKSAR. (Han Yan / Xinhua)

Highlighting Hong Kong's indispensable role as a bridge linking China and the UK as the Sino-UK partnership enters its "golden era", Chinese Ambassador to the UK Liu Xiaoming called for concerted commitment to the "one country, two systems" principle to maintain the SAR's long-term prosperity and stability.

From political stability, governance efficiency and regulatory quality to the rule of law, control over corruption, right to expression and accountability, many indicators are showing Hong Kong's improvement over pre-handover years

Liu Xiaoming,Chinese Ambassador to the United Kingdom

Liu made the remark late on Monday to an audience of over 200, including lords and members of parliament, during a celebration to mark the upcoming 20th anniversary of Hong Kong's return to China.

Praising Hong Kong's return as a landmark in modern Chinese history, the ambassador singled out a long list of achievements that show the "one country, two systems" principle has been hugely successful in the special administrative region.

Hong Kong's GDP has doubled. It remains a global center of finance, shipping and trade, and continues to be one of the freest and the most competitive economies in the world.

It houses the fifth-largest container port and is the eighth-biggest trading entity in the world.

Citing the right balance between the governance of the central government and the autonomy enjoyed by the SAR as an example, Liu emphasized that the central government is consistent in its strict adherence to the Constitution and the Basic Law and, as a result, Hong Kong is making steady progress in its democratic governance.

"From political stability, governance efficiency and regulatory quality to the rule of law, control over corruption, right to expression and accountability, many indicators are showing Hong Kong's improvement over pre-handover years," he said.

To fend off worries about the future of the principle and concerns about a "policy change" by the Chinese government, Liu called for better understanding of Hong Kong's reality and the Chinese government's policy.

"Hong Kong has been successful in the past two decades. That means 'one country, two systems' is a good principle," he said, "A good principle will not change."

Liu also cited President Xi Jinping as saying, "Whatever difficulties and challenges there are, our confidence and determination for the 'one country, two systems' principle remain unchanged, and our confidence and determination in implementing this principle remain unchanged."

He also reaffirmed the central government's staunch support for Hong Kong's ties and cooperation with the world. But he said China firmly opposes any interference in Hong Kong affairs by any foreign country for any reason.

"Facts must be respected," he said, "that Hong Kong has returned to China; China has sovereignty over Hong Kong; the 'one country, two systems' principle must be seen in its totality; Hong Kong-related issues must be handled appropriately."