BBC News on the web vs BBC News the programme, vs BBC worldwide (which is a seperate org inside the BBC), then there's regional BBC and the prime time talk shows (the hard hitting Andrew Neil and co).
So, when someone says "the BBC is biased against the left" or "the BBC is biased agains the right"; ironically they can both be right, and it's not an indicator of impartiality. It depends on which section of the BBC we're talking about.
And you're totally blind to the bits of the BBC you agree with; you will think those bits are the impartial ones.
* Pro the royal family since it is chartered by them.
* Against Scottish independence since it would lose 10% of its funding.
That said however they can't make things up, or overtly bury critical stories...but putting a softer slant on them wouldn't be unreasonable.
Their coverage of the Scottish independence referendum was laughably biased and often clueless.
They do seem to have an odd attitude towards Nigel Farage (UKIP & Reform) though, and kept putting him on Questiontime and the radio. It seems unclear why they would promote him so much given much of their other content.