I was that super-bright student, MaQueen, stuck in a bog-standard comprehensive. I still managed to get to Cambridge, despite coming from a home with two parents who did not have a single qualification between them. Yes, there were times when I wished lessons were more stretching, but I was able to pursue higher level learning outside of school, off my own bat.
My mother, also super-bright, ended up at a crap secondary modern that did not even offer the chance to take CSEs, purely because she was so nervous on the day that she flunked her 11 plus. It changed the course of her whole life. That cannot be right. Grammar schools will just reduce social mobility even further, I'm afraid. I don't feel the many should be sacrificed for the few. Why not provide extra lessons for the super-bright within comps and academies? The same outcome is reached for the top set, without ensuring the other 80% suffer life-blighting detriment.