I don't think the BBC is biased at all. I like many things, look at my wonders of nature thread.
Yes we know you don't think the BBC is biased, but can you explain why you think that? Otherwise it is mere assertion. As pointed out by NS earlier Corbyn would have received very different coverage had he made a mistake.
I also would hark back to a previous discussion about the way the two leaders are identified. Listen for the number of times Johnson is called "Boris" and the number of times Jeremy is called "Corbyn" and also listen closely to the inflections used.
You are not listening closely enough if you think there is no bias at work.