BEIJING accused two Chinese citizens today of spying for Britain, in the latest test of a relationship that has grown increasingly fraught.

In a message posted on social media, the Ministry of State Security, China’s main intelligence service, said it had uncovered a major espionage case involving a couple identified only by their surnames, Wang and Zhou, who were allegedly recruited by MI6. 

The ministry alleged that Mr Wang had been recruited by MI6 after going to Britain as a student in 2015 and was later joined by his wife.