The Facts

• Businesses and institutions across the world suffered severe disruptions of their services after an IT issue on Friday.

• Banks, airports and hospitals were just a fraction of those who reported outages and millions of people are believed to have been affected by the problem.

• While the issue affected Microsoft 365 apps and services, George Kurtz, CEO of the cybersecurity firm CrowdStrike, said his firm had been responsible, stating that the outage had been caused by "a defect found in a single content update for Windows hosts."