A US Senate delegation visiting Beijing in March expected its conversations with Chinese officials to be dominated by talk of a trade war between the two countries and President Donald Trump’s plans to meet North Korean ruler Kim Jong Un. Instead the five-member delegation — visiting on the same day that Mr Kim was in the Chinese capital — received an earbashing from Chinese officials seething over Taiwan.

The meetings came just weeks after the Senate had passed, and Mr Trump had signed, the Taiwan Travel Act, which formally encouraged more exchanges between US officials and their counterparts on the free, democratic and self-governed island. For Chinese officials, Taiwan is an inalienable part of their sovereign territory that they believe they will one day recover.

For Washington the “One China policy” is the “bedrock” of Sino-US relations. Under a diplomatic fudge that has lasted four decades, the US formally recognises Beijing but also maintains unofficial ties with the island of 23m people.