LONDON (Reuters) - Britain hopes that Hong Kong will make more progress towards democracy, Foreign Secretary Boris Johnson said on Thursday (June 29) in a statement marking 20 years of Chinese rule.

Britain returned Hong Kong to Chinese rule on July 1, 1997, under a "one country, two systems" formula which guarantees wide-ranging freedoms and judicial independence unseen in mainland China.

"As we look to the future, Britain hopes that Hong Kong will make more progress towards a fully democratic and accountable system of government," Johnson said in a statement.

"Britain's commitment to Hong Kong - enshrined in the Joint Declaration with China - is just as strong today as it was 20 years ago."

Beijing has promised Hong Kong's capitalist system will remain unchanged for "at least" 50 years until 2047, but it has not clarified what happens after that.

Chinese President Xi Jinping said on Thursday China would work to ensure a "far-reaching future" for Hong Kong's autonomy, but he faces a divided city with protesters angered by Beijing's perceived interference.