The independent panel commissioned by BBC board of governors has issued its report; it found no bias, but found the quality BBC’s coverage of the EU wanting:

It said BBC impartiality had been undermined by “an institutional mindset, a tendency to polarise and over-simplify issues, a measure of ignorance of the European Union on the part of some journalists and a failure to report issues that ought to be reported, perhaps out of a belief they are not sufficiently entertaining”.

…

UK officials at the European Parliament also condemned aspects of BBC coverage. In a submission, Dermot Scott, director of the parliament’s UK office, said the BBC “reinforced ignorance” by presenting arguments as if the main issues were about Britain’s membership of the EU or single currency.

The full report is available online.

Update: As pointed out in the comments, Straight Banana has an excellent post on this topic.