WHAT HAPPENED?

The scandal revolves around British firm Cambridge Analytica (CA) and how Facebook allegedly gave it access to the personal information of tens of millions of users without their knowledge.

Those initially affected had signed up to a personality quiz app, but this gave it access to their – and, crucially, their friends’ – private data.

According to whistleblower Christopher Wylie, CA then used this data to help clients all over the world influence voters and consumers – targeting people with personalised adverts.

An undercover investigation has exposed CA’s chief executive, Alexander Nix, boasting about how it essentially masterminded Donald Trump’s election campaign.

The damning footage also recorded senior CA executives bragging about how they could entrap election candidates with ‘beautiful’ Ukrainian sex workers and use ex-spies to dig dirt on them.

CA, largely owned by American billionaire Robert Mercer, is now facing questions from the UK’s Information Commissioner’s Office, which has applied for a warrant to search its offices in central London.

Facebook’s billionaire founder Mark Zuckerberg has been summoned by a parliamentary committee, while there are growing calls for the tech company to be investigated.

A backlash over the scandal has led to a fall in Facebook’s share price, with the company losing around £39billion, and £5.3billion wiped off Zuckerberg’s personal fortune.