Shortly before Sophie Zhang lost access to Facebook’s systems, she published one final message on the company’s internal forum, a farewell tradition at Facebook known as a “badge post”.

“Officially, I’m a low-level [data scientist] who’s being fired today for poor performance,” the post began. “In practice, in the 2.5 years I’ve spent at Facebook, I’ve … found multiple blatant attempts by foreign national governments to abuse our platform on vast scales to mislead their own citizenry, and caused international news on multiple occasions.”