The regulator says Facebook broke the law, breaching the UK Data Protection Act twice.
Tuesday, reports surfaced that the United Kingdoms Information Commissioners office has issued a fine to Facebook for $664,000 or about GBP 500,000.
"As we have said before, we should have done more to investigate claims about Cambridge Analytica and take action in 2015", said Erin Egan, Facebook's chief privacy officer.
Information Commissioner Elizabeth Denham launched a probe after it emerged an internet personality quiz was able to gather the data of up to 87 million Facebook users, by accessing not only the details of people taking the test who gave their consent, but that of their "Facebook friends", who had not agreed.
Don't miss out on the latest news and information.
Because of the timing of the breaches, the ICO said it was unable to impose penalties that have since been introduced by the European General Data Protection, which would cap fines at 4.0 per cent of Facebook's global turnover.
It is the largest possible penalty that can be handed out by Britain's information watchdog, which found the social media giant had broken the law by failing to safeguard millions of users' data. The ICO wants parties to undergo compulsory audits of their use of personal data, including the purchase of marketing lists and lifestyle information to help target voters.
"Fines and prosecutions punish the bad actors, but my real goal is to effect change and restore trust and confidence in our democratic system", she said.
Denham also called for the government to introduce a statutory code of practice for the use of personal data in political campaigns, adding that "this can not be at the expense of transparency, fairness and compliance with the law".
The Facebook probe is part of a wider investigation into the use of data in political campaigns, which the ICO launched previous year, the interim results of which are out today.
Since its entanglement with Cambridge Analytica became public, Facebook has pledged to review all third-party apps on the platform while introducing new transparency measures, including an online repository of all political ads that run on the site.
The ICO said its investigation is continuing and the next phase is expected to be concluded by the end of October.
The British fine comes as Facebook faces a potential hefty compensation bill in Australia, where litigation funder IMF Bentham said it had lodged a complaint with regulators over the Cambridge Analytica breech - thought to affect some €300,000 users in Australia.
"We have been working closely with the Information Commissioner's Office in their investigation of Cambridge Analytica, just as we have with authorities in the USA and other countries". Facebook will have an opportunity to respond to the findings, after which the office will render a final judgment.
- JetBlue crew rescues dog in distress with oxygen mask
- Treacherous Thai cave rescue bid enters day two
- Prince Louis makes first appearance with siblings at christening
- New Samsung Galaxy S10 'Leak' Reveals Possible CPU And GPU
- Eden Hazard still open to Real Madrid move
- Meghan and Harry Help Honor Royal Air Force
- Justin Bieber and Hailey Baldwin Share Steamy Kisses in NYC
- George Clooney is 'recovering' after scary scooter accident in Italy
- LONDON FALLING: US Embassy Warns Americans of 'VIOLENT' PROTESTS During Trump Visit
- 'Sharp Objects' star Amy Adams joins Reese Witherspoon admiration club