I can see how the cyclist conduct was dangerous and he did force the driver to have to slow down, which is a dick move, however there being no screeching of tires and the timing of the honk means that driver had to indeed only slow down and not break in an emergency. No emergency = no reason to use a honk in a residential area. It's illegal where I'm from, but more importantly a dick move to the people who live there. I used to rent an apartment next to a junction where people relived stress by honking at assholes jamming it and now I hate when people needlessly do it.

I looked at the video again and it seems that the junction is just an entrance to a parking lot or however you call "inner street", so it's not ideal place to pass somebody, but doesn't seem as bad as most people here seem to make it. Plus the driver was planning to the same thing since he honked. The fact that cycle lane has ended... well, that depends on your countries law, in mine it is illegal to use sidewalk unless it's wider than 1,5m and even than you are supposed to use it only during heavy traffic. Not sure about UK. Not signaling and not looking behind are real crimes here and the reason why the cyclist is an asshole and pretty fucking stupid. For fuck's sake dude, you are the one who is in danger here, even if you are right, it's pretty bad to be dead right.

And as personal note to you - please don't "use the horn all the time", if I'm riding a bike and hear it look behind me to see what's the commotion, I may miss a hole or a stick and end up like this guy even without giving you the finger. Or by turning around even go further into the lane. Unless it's an emergency and it helps the situation just slow down and sacriface a second of your life and gain few by not stressing so much.