FACEBOOK is rating users based on how "trustworthy" it thinks they are.

Users receive a score on a scale from zero to one that determines if they have a good or bad reputation – but it's completely hidden.

The rating system was revealed in a report by the Washington Post – and later confirmed by Facebook to The Sun – which says it's in place to "help identify malicious actors".

Facebook tracks your behaviour across its site and uses that info to assign you a rating.

Tessa Lyons, who heads up Facebook's fight against fake news, said: "One of the signals we use is how people interact with articles.

"For example, if someone previously gave us feedback that an article was false and the article was confirmed false by a fact-checker, then we might weight that person's future false news feedback more than someone who indiscriminately provides false news feedback on lots of articles, including ones that end up being rated as true."