The Chinese side expresses its strong condemnation of and firm opposition to "groundless slanders at China" and blatant interference in China's internal affairs by some politicians, a spokesperson for the Chinese embassy in Britain said Saturday.

Responding to a statement by British Foreign Secretary Dominic Raab and another joint statement by the Group of Seven foreign ministers and the High Representative of the European Union, both on issues related to Hong Kong, the spokesperson said that the authority of China's National People's Congress's decision to improve the electoral system of Hong Kong "brooks no challenge."

"This decision was made by China's highest organ of state power," said the spokesperson, adding that it is in line with the provisions of the Constitution of China and the Basic Law of the Hong Kong Special Administrative Region, conforms to universal practice, and constitutes a necessary step to uphold and improve the mechanisms of "one country, two systems."

Improving the electoral system in Hong Kong and implementing the principle of "patriots governing Hong Kong" will promote the sound development of the democratic system in Hong Kong, better safeguard the rights, interests and freedoms of Hong Kong citizens, and ensure the steady and sustained practice of "one country, two systems," said the spokesperson.

Moreover, the so-called "China breaches the Sino-British Joint Declaration" is a non issue, the spokesperson said, adding that the core content of the Joint Declaration is to ensure China resumes exercise of sovereignty over Hong Kong and its historical mission was completed at the handover.

"The UK has no sovereignty, jurisdiction or right of 'supervision' over Hong Kong after the handover, and it has no so-called 'obligations' to Hong Kong citizens. No foreign country or organisation has the right to take the Joint Declaration as an excuse to interfere in Hong Kong affairs, which are China's internal affairs," the spokesperson said.

China strongly opposes any external interference, said the spokesperson, adding that Hong Kong is a special administrative region of China.

"How to design and improve its electoral system is purely China's internal affair and brooks no external interference," the spokesperson said.

The attempts of politicians from the relevant countries and groups, including Britain, to distort facts and impose unwarranted accusations on China will in no way change the judgement of the just force in the international community, said the spokesperson.

"China has the will, determination and capability to safeguard its national sovereignty, security and development interests. We urge the relevant countries and groups, including the UK, to immediately stop interfering in Hong Kong affairs, which are China's internal affairs," said the spokesperson.