Heads of FBI, MI5 Issue Joint Warning on Chinese Spying

LONDON—The heads of the FBI and Britain’s domestic security service issued sharply worded warnings to business leaders about the threats posed by Chinese espionage, especially spying aimed at stealing Western technology companies’ intellectual property.

In a rare joint appearance on Wednesday at the headquarters of MI5, Christopher Wray, director of the Federal Bureau of Investigation, and Ken McCallum, director-general of MI5, urged executives not to underestimate the scale and sophistication of Beijing’s campaign.