Weighing up the competing claims, the judge said PC Rowland was "not the sort of man who would have had the wit, imagination or inclination to invent on the spur of the moment an account of what a senior politician had said to him in temper."
In other words, the judge agreed that that PC Rowland was a pleb. Far too much of a pleb, ironically, to have invented being called a pleb. (They probably didn't do Latin at his school.) Sometimes, the class system bites you in the bum.
PC Rowland is reportedly delighted. If he noticed that the judge was calling him a pleb, he refrained from comment. After all, the judge thought him "a rather old-fashioned officer", so how could he do less than reciprocate and think that the judge was a real old fashioned gent?
Gawd bless us, every one.