- 28 August 14:11
In his first foreign policy speech, the PM said the closer economic ties of the previous decade had been "naïve."
He said the UK now needed to replace wishful thinking with "robust pragmatism" towards competitors.
But he warned against "Cold War rhetoric," adding that China's global significance could not be ignored.
Mr. Sunak has faced pressure from Tory backbenchers to toughen the UK's stance on China since he took over as Tory leader and UK prime minister last month.
The speech to the Lord Mayor's Banquet in London comes after protests in China over the weekend against the country's strict Covid lockdown laws.
Police have made several arrests, and a BBC journalist was detained while covering a protest in Shanghai on Sunday. He was beaten and kicked by the police during his arrest and held for several hours before being released.
Mr. Sunak told the audience of business leaders and foreign policy experts that, in the face of the protests, China had "chosen to crack down further, including by assaulting a BBC journalist".
"We recognize China poses a systemic challenge to our values and interests, a challenge that grows more acute as it moves towards even greater authoritarianism," he said.