Obviously a f**wit at the wheel,a few aboutI had a situation the other day M5 southbound. Moved into middle lane and was approaching a Nissan juke that had been sitting in the middle lane for a few miles with ample opportunities to move to the inside lane as I had been travelling behind. As I got closer to the Duke I was prevented by another car in the outside lane travelling just quicker than me, it was at this point I considered tapping the brake as I was on cruise, the Duke must have looked in the mirror saw me and swept over to the inside lane quite violently, i passed and as i looked in my mirror the car swept back into the middle lane as urgently as it had moved before, even though there was no vehicles in front of it for quite a distance, enough for me to move to the inside lane and continue on. What exactly was going through (her) mind is anyone's guess. Maybe inside lane is trucks transit only. Get out of it quick.