People only see bias when it misses out their view.The thing is, unlike ITV which is becoming increasingly left-wing focused (and starting to force this heavily on the viewers through both soaps and ITV Daytime - GMB/This Morning/Loose Women), the BBC remains rather neutral and independent in it's broadcasting, which is a precious thing in this age of bias and one-sided views.
The BBC is biased because they typically use only the official story from the authorities, or the source material like a university.
For example here are the main news stories in England today according to BBC. https://www.bbc.co.uk/news/england
Can you find any story on the page in which there are any conflicting views presented?
Also you can probably see the stories the BBC highlight are often of little importance to the normal person.