The database, known as MS Celeb, contained images of around 100,000 well-known people.

An investigation by the Financial Times found that global tech companies and military researchers were using the database to train their facial recognition software.

Microsoft told the FT that the site was intended for academic purposes and had been removed because it was run by an employee who had since left the company.

Last year, Microsoft’s president, Brad Smith, asked Congress to regulate facial recognition technology. The company also turned down a request from police in California to use its facial tech in body cameras and cars.

Last month, San Francisco became the first US city to ban the use of facial recognition tools by agencies including law enforcement and transport authorities.