As argued before, the fact that the BBC gets complaints from both sides isn't proof that the BBC is impartial.
That point duly made...here are two Twitter comments on the subject of bias that were made at almost exactly the same time today:
ChrissieSilverSurfer @ChrissieOAP 2h. @BBCNews showing UKIP conf @SkyNews showing @Ed_Miliband on soapbox speech in full.#BBCbias at it's worse
james cooper @vicarjim4 2h bbc at labour party confernece not started yet. is that bias or has ED offered them more money. do they know UKIP conference on now?