I always found it hilarious that the school I went to was always telling us how they were the best in the area, yet they always came at or near the bottom of league tables for the area, in the bottom 200 nationwide and always had a steady stream of people no other school would take.
The year I left, only one person got A*s for maths and science, only one person got As for maths and science and everyone else (out of 160 or so) got Bs and below (don't remember the grades for other subjects). I know grades aren't everything, but surely if they were as good as they claimed, more of the smarter people would be wanting to go there. All of the smart people I knew in juniors deliberately made sure they didn't go there.