Early this year, a British tabloid ran a hyperbolic article on climate change, claiming that world leaders had been "duped" by climate data that had been manipulated. It wasn't unusual for the outlet or the article's author to make badly misleading claims about climate research, and our own investigation into the underlying disagreement showed that the piece actually boiled down to a dispute about how best to archive data. These sorts of misrepresentations happen dozens of times a year.
But something unusual did eventually happen as a response to the article in the Mail on Sunday: a UK press watchdog determined that the article breeched the Editor's Code of Conduct. Mail on Sunday was subsequently ordered to prominently display the inaccuracies above the article itself.
The judgement was handed down by IPSO, the UK's Independent Press Standards Organization (IPSO). It maintains an Editor's Code of Conduct, which sets standards for handling a variety of issues; the one relevant here is the section on accuracy. The Mail on Sunday belongs to IPSO and agrees to be bound by its rulings.