I'm all for banning grammars in their current form for these very reasons. This system is so GROSSLY unfair it'd be shocking that it is still perpetuated EXCEPT that many of those who are in a stronger position to change the system actually benefit from the status quo, ie those who can afford to prep and thus 'save' themselves £80k- ish.
Fwiw, I'm ex- grammar, but I object strongly to those who'd say 'YOU benefited from a grammar yet you seek to deny others that opportunity'- to which I'd reply that yes, but the establishment I called a state grammar back in 1973 isn't the same beast any more at all. There was one girl in my class of 30 who came from a prep school. Now 75% of the girls there come from private preps. That just about sums up my opinion.
Unless we find a truly fair way of testing DCs for entry , perhaps we need to 'weight' the results of the 11+ depending on whether that DC went to prep or was tutored. And I know the latter is impractical because as the article tells us, tutoring is a secretive and shady area! You'd be depending on other parents to 'shop'. Which I'm sure they'd be only too happy to do IF their 'outlay' didn't pay off!
I'd also perhaps advocate a re-assessment at 12 or 13, to allow an 'out' to those over-prepped DCs who squeaked into grammar but have struggled ever since to re-evaluate their position AND to allow those who didn't get in at 11+ another go.
I will readily say there were certainly girls in my grammar who patently shouldn't have been there, and I've subsequently met women, as an adult, who achieved pretty much the same exams as I did but out of secondary moderns.
11 is WAY too young to making these sort of divisions.
Finally, a great quote:
The Left Wing hate grammars because they entrench privilege. The Right Wing love grammars because they entrench privilege.