I am a product of the Grammar School system and as a mechanism for producing middle class professionals it was without doubt a system without peer. Every year the local newspaper would publish the group photograph on page 4 or 5 of the dozen or so kids who were off to Oxbridge. Since the death of the Grammar Schools anyone from my town getting a place at Oxbridge seems to be worthy of a front page spread.
The key phrase however is, in my opinion "a mechanism for producing middle class professionals" The Boys Grammar schools produced the Doctors, Lawyers, Engineers, Architects, local Government Officers, Junior Civil Servants (Senior Civil Servants were Independent school and then Oxbridge), Teachers, Junior Officers for the Armed Forces (Senior Officers were like Senior Civil Servants), small businessmen, etc. As a matter of interest the Hasrtlepool Girls High School, even in the 70's, was still producing the wives of middle class professionals, the nurses to the Doctors from the Grammar school, the Secretaries for the local Captains of Industry, etc.
What made Grammar schools ultimately indefensible in my opinion was the social stigma attached to "failing" the 11 plus if you were not selected for Grammar School. This wasthe class system at its worst and showed how unbalanced society's values were at the time and in many ways the imbalance continues to this day. It was a failure to be practical rather than academic. Society valued the Lawyer over the car mechanic, the accountant over the electrician, the Civil Servant over the assembly line worker. Blue Collar Bad, White Collar Good, but Blue Blood Best!
As a system it might have promoted social mobility from the working class to the middle class but it also imposed a glass ceiling at the point where "He's a Grammar School Oik" prevented anyone reaching the real heights unless they were very, very talented and/or lucky.
So over all there was a case for destroying the Grammar schools.
However, what was put in their place was worse. People who want a return to Grammar schools are actually calling for the re-introduction of a bad system that is only preferable to the current system as the lesser of two evils. The theory of comprehensive education, equality of opportunity for all, is exactly the one I support. However, comprehensive education was hijacked by the left wing bleeding hearts to not be equality of opportunity but equality of achievement. Properly streamed Comprehensives are infinitely preferable to Grammar Schools. Teaching by ability group within a mix ability population. Kids may be in the top group for one subject and the bottom group for another, why not? My daughter excels at English, History and Sociology but struggles with Maths, Chemistry and Physics. She has offers from several top Universities to read Law. Under the old system she would not have been encouraged to do that!
So overall I'm glad the Grammar Schools are gone and I wouldn't like to see them back. What I would like is Comprehensive Education run properly. Where it works it works well, where it doesn't work then no amount of Grammar Schools will fix it.