Actually it is not bipartisan; it is required to be neutral, regardless how how many political parties (or political / economic ideologies) there are.

Alright, that's what I actually meant when I said bipartisan - that it does not support any parties by definition. I know, wrong word.

That may be your belief but there are plenty of people who think otherwise. http://biasedbbc.org/

You can look at the tags to see the bias of biasedbbc. I'm sure there are plenty of people that would argue that if not pro-conservative, the BBC neglects many of the issues that would be detrimental to current government - the BBC completely ignored phone hacking, the privatisation of the NHS, among others. It's still probably significantly more neutral than almost any corporate controlled broadcaster though.

The "bias" in the BBC is primarily to "favor" the current government of the time by not running highly controversial stories until they have become mainstream. They also avoid running purely political stories outside their politics section, like "the privatisation of the NHS" (which is a Labour party press release, not a thing that has happened to report on).

What they don't do is run directly biased stories; they're "neutral" in the content they put out, and any perceived bias is the result of their tendency to hold off on running boat-rocking stories. You could easily argue that this is a bias in itself, but it's not a partisan bias and it's hard to see how they could do this differently; it comes from their entirely legitimate fear that if they annoy any current government too much then they might lose the license fee advantage.