China's ambassador to the UK has been summoned to the Foreign Office over Beijing's "aggressive and wide-ranging escalation" against Taiwan.
Foreign Secretary Liz Truss said she had ordered officials to call in ambassador Zheng Zeguang to explain his country's actions in recent days, which have seen missile launches and incursions into Taiwanese waters and air space.
The move comes as China appeared to wind down wargames near the self-governing island amid high tensions between the two sides.
However Beijing has repeated military threats, refusing to rule out the use of force against Taiwan which it claims as its own territory.
"We will always be ready to respond with the use of force or other necessary means to interference by external forces or radical action by separatist elements," a Chinese statement said.
"Our ultimate goal is to ensure the prospects of China's peaceful reunification and advance this process."
China has claimed that its actions around Taiwan, which saw its warships and air force planes enter Taiwanese waters and air space, were prompted by a visit to the island by US House Speaker Nancy Pelosi.
Taiwan says such visits are routine and that China used her trip merely as a pretext to up its threats.
Ms Truss said in a statement: "The UK and partners have condemned in the strongest terms China's escalation in the region around Taiwan, as seen through our recent G7 statement.
"I instructed officials to summon the Chinese ambassador to explain his country's actions.
"We have seen increasingly aggressive behaviour and rhetoric from Beijing in recent months, which threaten peace and stability in the region.
"The United Kingdom urges China to resolve any differences by peaceful means, without the threat or use of force or coercion."
Taiwan has been self-governing since nationalist forces fled there in 1949 after the communists took control of China, and is considered to be a rebel province by Beijing.