Hong Kong student activist Joshua Wong joins London protests against President Xi Jinping's visit

Student activist Joshua Wong Chi-fung led protesters from Hong Kong in opposing London's deepening ties with Beijing, as he attended a human rights rally in the British capital yesterday.

Wong's attendance at the rally coincided with President Xi Jinping's first state visit to Britain - during which British Prime Minister David Cameron hopes to secure trade deals with Beijing worth billions of dollars.

Speaking to the South China Morning Post, Wong attacked Beijing for breaking its promise on the 1984 Sino-British Joint Declaration that paved the way for the 1997 handover and made provisions for democratic elections in 2017.

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"Why is the UK seeking further cooperation with the Chinese government when [Beijing] broke its promise on the Joint Declaration?" he asked.

"I worry about whether 'one country, two systems' will result in one country, one system.

"The new generation is demanding the right of self-determination because we are really afraid that [after 2047] Hong Kong will merge with China and we will not have rule of law, separation of power and freedom of speech."

The student activist is in the country to speak at British universities including the Oxford Union, the London School of Economics and the School of Oriental and African Studies about democratisation in Hong Kong.