I do remember that the Glasgow Media Group, a media monitoring organisation associated with Glasgow University, published a report in the Eighties, updated in the Nineties, detailing their evidence that the BBC tended to take the side of employers in industrial disputes
This often came about through unthinking assumptions, i.e. a strike was "a bad thing" rather than "refreshing evidence that the working class are willing to struggle for economic justice".
I think this remains the most valid critique of the BBC - I don't think they go out of their way to bend the facts, and especially living here in China where the media is a whole other thing, I appreciate the breadth and range of differing viewpoints they give space to, but they have their worldview and assumptions and it colours what they tell you - as in the example above, as in the reporting of the Balkans conflict, as in their reporting of Islam, and so forth