Thames water "Lane Hogging" at 55/60mph on the M4, Dangerous, dumb also illegal.
This lane hogging is dangerous because some drivers will finally get angry at them and drive very badly to get under them. They also cause traffic jams and cause further dangerous driving as those behind are jousting for position. This needs more enforcement.
Saw this driver with phone in hand today held right up in view, definitely distracting, not good.