This graphic is the most illuminating one of all: just 2% of movements on the M25 South West Quadrant are “through” ones, the other 98% turn on, off or both within it. A huge proportion are local movements, there because other road or rail/bus options are even worse!
78% of the traffic on this bit of the M25 is traveling to or from somewhere fairly local.
Only 2% is staying on the M25 all the way without turning off.