[asuffield]

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.