Must be a wanker, its a BMW and he has the right to do whatever he wants with no regard for any other drivers. With the risk of being just as wanky, I'd have pulled over in front of him. I hate cunts that undertake to try and make a point.
Front Cam confirms you are lane hogging. No excuse for the undertake but pot, kettle and black come to mind. Just because everyone else is in the right lane does not mean you have to stick with them.
I Support Vehicle Bombings With A Car Stuffed With Bombs