The curious case of Candace Claiborne shows the depths Chinese intelligence services will go to secure sources, and the weaknesses in US national security.

Having worked on classified weapons research for the United States, and played a role in developing China’s first atomic bomb, Qian Xuesen sparked the social credit system that will track – and possibly control – Chinese citizens’ behaviour

A number of those accused have had their cases dropped abruptly, but the damage to their reputations and careers has already been done

A German physicist recruited under a programme to attract foreign scientists to China has charged his host with diverting funds - and other scholars hired under the plan seem to share his misgivings.