"The British side allowed certain figure from the Taiwan region to visit the UK and arranged for relevant official to meet with said person. This move seriously violates the one-China principle and the basic norms of international relations," the embassy spokesperson said in a statement.
The document read that the meeting sent a "seriously wrong signal" to Taiwan's independence separatist forces and interfered in China's internal affairs, adding that Beijing strongly deplored and firmly opposed the move.
"China urges the UK to earnestly abide by the one-China principle and basic norms governing international relations, stop any official exchanges with the Taiwan authorities, and stop emboldening separatist forces for 'Taiwan independence'. We want to make it clear to the UK side that any actions that undermine China's interests will be met with resolute responses," the statement said.
Taiwan has been governed independently of mainland China since 1949. Beijing regards the island as its province, while Taiwan maintains that it is an autonomous entity but stops short of declaring independence. Beijing opposes any official foreign contacts with Taipei and regards Chinese sovereignty over the island as indisputable.
The latest escalation around Taiwan took place in April after Taiwanese President Tsai Ing-wen met with US House Speaker Kevin McCarthy. Beijing responded by launching massive three-day military drills near the island in what it called a "warning" to Taiwanese separatists and foreign powers.