I'm aware that I've been cluttering up the 11+ tutoring thread with discussions the OP said she didn't want, on the merits or otherwise of grammar schools in principle, so I'll stop doing that and start my own thread!
So, I genuinely don't get why so many people think separating children by ability (or potential, or however you try to do it) at 11 or even younger is a good thing. Why will they benefit more from that than from properly differentiated teaching in a comprehensive school? And what about the children who aren't selected? How does a selective system benefit them?
Genuine questions. I'm strongly in favour of comprehensive education, but would really like to better understand the arguments against.