Despite attempts by the British government to reset ties with the world's second-largest economy, relations have remained strained by accusations of spying and tensions over the fate of Hong Kong, a former British colony.

Starmer became the first British prime minister to meet Chinese leader Xi Jinping in over six years in November 2024, a sign that relations were improving.

But speaking at the annual Lady Mayor's Banquet on Monday, Starmer said China "poses real national security threats", and said London would continue to raise human rights issues with Beijing.

On Tuesday, the Chinese embassy in London said it "firmly opposes the British side's remarks... that groundlessly accuse China and interfere in its internal affairs".

"China's development poses no threat to any nation," it said in a statement, adding that Starmer's remarks were "erroneous".

Starmer promised Monday that his country's China policy would no longer blow "hot and cold".

Describing the failure to have a relationship with China as a "dereliction of duty", he called for a "serious approach".

"You can work and trade with a country... while still protecting yourself," the prime minister said.

He said he would seek to engage with China on trade, nuclear proliferation, AI, climate change and other issues -- but also vowed to give security services updated powers and tools to deter what he said was the security threat posed by Beijing.

In November, Britain's domestic intelligence agency warned that Chinese spies disguised as headhunters had targeted parliamentarians online.

That came after Britain's public prosecutor dropped a high-profile and politically charged case against two men, one a former parliamentary researcher, accused of spying for China.

China denied the allegations in both instances.

A proposed vast new Chinese embassy in London has also triggered security and rights concerns.

The UK government is due to decide whether to grant permission for the embassy by December 10.

Starmer also said Britain would continue to raise human rights concerns with Beijing, including over "curtailment of freedom in Hong Kong".

The Chinese embassy responded Tuesday that Hong Kong issues were China's "internal affairs".

"Britain has neither the qualification nor the right to make unfounded remarks or interfere improperly," it said.