However, Sky News notes that the £500,000 fine will be "pocket change" for a company valued a year ago at around $590bn (£445bn).
The proposed fine is the largest issued by the Information Commissioner's Office (ICO) and the maximum allowed under the 1998 Data Protection Act, which applied at the time of the breaches.
The penalty could be just the first in what might become several fines for Mark Zuckerberg as the Information Commissioner's.
Future violations will be able to be punished much more strictly, however: Under GDPR, the EU's new data protection legislation, companies can be fined up to €20 million or 4% of their global annual turnover, whichever is higher.
Media Committee chairman Damian Collins commented: "Given that the ICO is saying that Facebook broke the law, it is essential that we now know which other apps that ran on their platform may have scraped data in a similar way". In an accompanying report, Elizabeth Denham, the United Kingdom information commissioner, expressed unease with the "significant shortfall in transparency" from tech companies, political parties and others that harness sensitive bits of information online.
Facebook faces a £500,000 ($665,000) fine from the UK's data protection watchdog, the ICO, for failing to protect netizens' info nor tell them how their data would be harvested by apps.
As part of the Wednesday's announcement, the watchdog also announced a criminal prosecution against Cambridge Analytica's parent firm, SCL Elections, over allegations that it didn't hand over evidence related to the data misuse probe.
The final decision regarding the fine will be made after Facebook issues a response to the notice. "Trust and confidence in the integrity of our democratic processes risk being disrupted because the average voter has little idea of what is going on behind the scenes".
Cambridge Analytica used data from millions of Facebook accounts to help Donald Trump's 2016 presidential election campaign. "But this can not be at the expense of transparency, fairness and compliance with the law".
That's why greater and genuine transparency about the use of data analytics is vital'. It's also about half of what the Spanish data protection authorities previous year extracted from to the firm for privacy failings.
"The scandal took place before new European Union data protection laws that allow much larger fines came into force", the broadcaster says.
The ICO said its investigation is continuing and the next phase is expected to be concluded by the end of October.
"The alleged breaches surround the circumstances in which a third party, Cambridge Analytica, gained unauthorized access to users' profiles and information".
A Russian Internet company with links to the Kremlin was among the firms Facebook gave an extension allowing them to collect data on unsuspecting users - even after the practice was supposedly stopped, CNN reported Tuesday.