There is a city that has scanned the faces of more than 3 million people on the street, and it's not in China, but in Europe

London police say real-time facial recognition has helped drive thousands of arrests after scanning more than 3 million faces.

The technology is being used on city streets, including in Croydon, marking a major expansion of public biometric surveillance.

Activists and groups like Big Brother Watch warn it threatens privacy, can amplify bias, and normalizes mass monitoring.

The debate now centers on whether the policing benefits justify the civil liberties risks and legal precedents being set.