I think that selective education was, and remains, a good idea. The idealisms of non selective clearly are utter 'dangle berries', as its the clever ones getting dragged down to lowest common denominator, rather than the slower learners getting dragged up to a higher level. Every child should have the most suitable education for them. Some kids thrive on academic work, others might be better at more practical tasks.
I should point out, I was lucky enough to go to a Grammar school. Aylesbury Grammar School. I possibly didn't deserve to go as I'm wasn't particularly bright, but the 12+ (year later in Bucks) was basically solving logic problems, which is what I'm good at.
I'm not sure Aylesbury Grammar was the best place for me, as although I was good at the science type stuff, the arts were difficult, particularly languages. The headmaster, Mr Smith, was an arse (little things like purposely slamming doors in your face), and once it became apparent I had no interest in going to Oxbridge, I was virtually given up on.
I was bullied a fair bit (and not just by pupils), which my defence mechanism was to retaliate, which meant I was always up before one of the deputy heads, Mr Roe (the hardnut) in particular, on at least a weekly basis.
I could of got good O and A Level results, but I was already finished with the system by then. I only stayed on to A levels because Mum insisted, and there were no jobs at the time.
On my very first day I got a detention within minutes as Mum hadn't had chance to sew on the school badge to my (2nd hand) blazer. Also, as a naïve 11yr old, I also went for a piss, and saw a new starter and an older boy leave the same cubicle. The new boy was crying and didn't look happy. I never went for another piss at that school again. Even now, I don't go often, possibly being one of the causes of my gout.
So, when I say its important that kids go to the "right" school, its not just a case of going to the academically best school. They need to be able to fit in, and grow at this important age. Just like Uni v apprenticeship, Grammar v Comp shouldn't be classed as success or failure.