There is very little if anything to show that working class children became socially mobile - the argument often made and the one repeated now.
Of course we all want the most talented to be able to make use of those talents but there is no real evidence that the Grammar Schools actually achieved this. The Grammar School system was not as popular as some make out in the 1950s/60s. The Crowther Report, commissioned by Conservative Secretary of State David Eccles, stated in 1959 that the rapid rise in school rolls after the war "has largely increased public clamour against a competitive element in grammar school selection, which seems to parents to be contrary to the promise of secondary education according only to "age, aptitude and ability"
"In the grammar school period, while 33% of those whose father's profession was "higher professional" got onto a degree course at university, only 2% of those from a skilled manual background did so and just 1% of those from a semi-skilled or unskilled background." (Robbins Report)
We must, must, must ensure a good education for all as the economy hollows out and very few of the typical well paid blue collar or lower level white collar jobs that took people into a life their parents could not have contemplated, disappear with technology. The middle class is feeling squeezed because of this and because they are becoming aware that their children will find things more difficult and, as always, they want the system to work for them - understandably. But as we will either be offering low-paid, insecure work or high paid, highly skilled work and those in the highly skilled jobs must be able to continue learning and change direction of learning through their lives. For the country to succeed and bring in those highly skilled jobs every one needs the best possible education, not just a few.