China‘s military has sharply criticised the passage of a British warship through the Taiwan Strait, labelling it a deliberate attempt to “cause trouble”, as Taiwan’s president ordered heightened surveillance in response to Beijing’s military activities.

The Eastern Theatre Command of China’s People’s Liberation Army condemned the HMS Spey’s Wednesday sailing as “public hyping”, stating that its forces closely followed and monitored the patrol vessel.

Beijing asserts that the narrow waterway, which separates mainland China from Taiwan, constitutes Chinese waters.

In contrast, Britain’s Royal Navy maintained that the HMS Spey’s transit was a “routine navigation” conducted as part of a “long-planned deployment” and “in full compliance with international law”.

This stance aligns with Taiwan, the United States, and many of their allies, who contend that the strait is an international waterway.

China, however, views Taiwan as its own territory, further complicating the legal and political status of the strait.

“The British side’s remarks distort legal principles and mislead the public; its actions deliberately cause trouble and disrupt things, undermining peace and stability in the Taiwan Strait,” it said in a statement.

“Troops in the theatre are on high alert at all times and will resolutely counter all threats and provocations.”

Taiwan’s government welcomed the sailing.

“The foreign ministry welcomes and affirms the British side once again taking concrete actions to defend the freedom of navigation in the Taiwan Strait, demonstrating its firm position that the Taiwan Strait is international waters,” the ministry said in a statement.

China has over the past five years stepped up its drills around Taiwan, including staging war games that have alarmed Taipei, Washington and Tokyo.

Taiwan President Lai Ching-te on Thursday ordered defence and security units to step up their monitoring and intelligence efforts in response to China’s military activities, which he said have not abated even as tensions rise in the Middle East.

On Friday morning, Taiwan’s defence ministry reported another spike in Chinese movements close to the island over the previous 24 hours, involving 50 aircraft, concentrated in the strait and the top part of the South China Sea.

The last time a British warship sailed through the strait was in 2021, when HMS Richmond was deployed in the East China Sea en route to Vietnam. Chinese military followed it at the time and warned it away.

The latest passage comes at a time when Britain and China are seeking to mend their relations, with Prime Minister Keir Starmer expected to visit Beijing later this year – the first trip to the country by a British leader since 2018.

U.S. Navy ships sail through the strait around once every two months, sometimes accompanied by allied nations.