The BBC is supposed to handle this sort of thing itself, and the only people who can formally hold it to account are the BBC Trust, and the way their complaints system works, and indeed their self-analysis, since the mid-'00s, ensures that they brush off any and all criticism from the '00s and beyond, whilst obsessing about shit that happened in the 1990s and actually doesn’t matter at all.
They have a specific doctrine of impartiality. Up into the '00s, this simply meant impartiality, in like, the everyday sense - i.e. honest reporting which didn’t favour a side but tried to get to the truth of the matter, tried to be objective, tried to find out the facts.
In the '00s, certainly by 2010, something changed. I think the 24-hour-news cycle was part of it, but there were people trying to “reform” the BBC, constantly claiming it was “for the better” through the whole period (both politicians and BBC insiders) and whatever the cause was, the end result that impartiality in the common sense, common language sense, of trying your best to find out the truth was, was replaced. It was replaced with the Bothsidesism version of “impartiality”, which is to say, not actual impartiality at all, but rather, assigning two “sides” to every issue - even ones that didn’t have two “sides” but rather multiple perspectives - or where one “side” was objectively, demonstrably right, and the other “side” were self-publicists, actual crooks, undeclared but demonstrably paid PR people, and so on.
The end result was that both assigned “sides” of any issue would get equal airtime, even if one of them was just complete drivel.
Climate change was the key example, and I see it still is. Up into the early '00s, BBC reporting on it was significantly above average, but that rapidly changed. By say, 2010, they were giving climate change deniers more airtime than they’d ever, ever had before, and treating them as if they were serious people with a serious point. They did this even when it was obvious moronic. For example, an ex-politician who is literally paid hundreds of thousands by polluters (yet is denying he works for them, saying he works for a “trust” or a “thinktank” or w/e), is in an interview with two scientists. Both scientists are saying climate change is real, being extremely clear, but between them they’re only allowed as much airtime as the crooked ex-politician. So we have to have his horseshit for 5 minutes and the real facts are only allowed 5 minutes.
On top of this, because it wasn’t “sexy” as a subject, the BBC put second and third rate editors and interviewers on this stuff, so the deniers always got let off incredibly easily, even when they outright lied or mislead in really crude ways anyone reading this thread would have picked them up on. And when the scientists tried to do this, half the time the interview cut THEM off.
Every single head guy the BBC has had since 2010 has 100% been behind this bullshit, note. Absolutely willing to defend it to death. Again climate change has been really obvious as an issue here - the BBC head honcho defended their shit constantly until 2018 when finally a report from the BBC themselves was like “We done fucked up” and he promised to stop the Bothsidesism on it (but only on it). He was lying though - they didn’t stop it, they just did it less.
The BBC also has an issue all the way back where basically the more like “the average BBC staff member” you are, the more coverage you get. Aka structural racism, except it’s more than that. So if you’re poor, or black (or Asian in the '90s), a Muslim (or an atheist in the '90s), or whatever, or not generally white, well-educated, and preferably “lite” Christian or “lite” Jewish, you’re going to get short shrift. Which has combined with the Bothsidesism in unpleasant ways a number of times. It ensures the BBC always treats poor people with utter contempt, too, especially if they’re protesting about something genuinely harmful.
TLDR: The BBC literally decided to change the meaning of impartiality from impartiality to “Bothsidesism” in like 2005. And has been a trashfire ever since.