Social media giant Facebook now known as Meta Platforms, faces a £2.3 billion plus class action in Britain over allegations it abused its market dominance by exploiting the personal data of 44 million users.
Liza Lovdahl Gormsen, a senior adviser to Britain's Financial Conduct Authority (FCA) watchdog and a competition law academic, said she was bringing the case on behalf of people in Britain who had used Facebook between 2015 and 2019.
The lawsuit will be heard by London's Competition Appeal Tribunal.
It alleges tjat Facebook made billions of pounds by imposing unfair terms and conditions that demanded consumers surrender valuable personal data to access the network.
Quinn Emanuel Urquhart & Sullivan, the law firm representing Lovdahl Gormsen, has notified Facebook of the claim.
Facebook said people used its services because it delivered value for them and "they have meaningful control of what information they share on Meta's platforms and who with."
The case comes days after Facebook lost an attempt to strike out a competition lawsuit by the Federal Trade Commission (FTC).
This marked one of the biggest challenges by the US government against a tech company in decades as Washington attempts to tackle Big Tech's extensive market power.
"In the 17 years since it was created, Facebook became the sole social network in the UK where you could be sure to connect with friends and family in one place," Lovdahl Gornsen said.
"Yet, there was a dark side to Facebook; it abused its market dominance to impose unfair terms and conditions on ordinary Britons, giving it the power to exploit their personal data."
Lovdahl Gormsen alleges Facebook collected data within its platform and through mechanisms like the Facebook Pixel, allowing it to build an "all-seeing picture" of Internet usage and generate valuable, deep data profiles of users.
Opt-out class actions, like Lovdahl Gormsen's, bind a defined group automatically into a lawsuit unless individuals opt out.