British regulators are to investigate whether Facebook broke data protection laws by letting researchers conduct a psychological experiment on unknowing users.
The Information Commissioner's Office said it would be asking the social network questions and would also liaise with Irish regulators, as the company's European headquarters are in Dublin.
Although the regulator has not specified which laws the site may have infringed, it has the power to force companies to change their policies and can also issue fines up to £500,000 for breaching the Data Protection Act.
More top news
Samples from 95 buildings in 32 local authority areas have failed fire safety tests - 100% of the cladding samples submitted.
But which member of the royal family spends the most?
The web giant must pay £2.1bn, the European competition watchdog has ruled.