WHY do we not cherish state education in the same way that we unite around the NHS?

For one part of the answer, we need to go back to the 1944 Education Act which established free secondary education for all, but in a deeply divisive way.

Young people were assigned to one of three types of schools — grammars, secondary moderns or technical schools (although the latter did not really take off) as the result of the 11-plus, a test taken before puberty.

Thus, the post-war school system, while offering every child a chance at a basic education, reflected and reproduced the basic class patterns and prejudices that had ruled England prior to the second world war.

The 11-plus was based on IQ research of the 1920s and 1930s and influenced by Sir Cyril Burt, who drew in his work on eugenic ideas from the early 20th century. Burt’s work was later discredited.

In practice, grammar schools tended to admit children from better-off families, taking very few working-class or poorer pupils.

Much grammar school education was poor and those working-class children who did get into grammars often left with fewer qualifications, while secondary moderns, the schools for the vast majority, were under-resourced and largely treated with disdain.

There were exceptions, such as St George’s in the East, in London, where radical educator Alex Bloom provided a richly creative education for his largely working-class pupils. The film To Sir, with Love is based on the memoir of one teacher at the school.

Overall the stark class injustice of the tripartite system, and the sheer waste of human talent it represented, fuelled the growing movement for comprehensive reform — its aim to offer full educational and life opportunities to all children.

This was supported across the political divide and led to the reorganisation of education along comprehensive lines from the mid-’60s onwards.

Despite its many setbacks and the continued ambivalence of many in the political Establishment, comprehensive education has had extraordinary successes.

Coupled with the rise in the school leaving age, the number of students in education at age 17 rose from 31 per cent to 76 per cent in 2011 and those achieving a degree rose from 68,000 in 1981 to 331,000 in 2010 — an almost five-fold increase.

Both the percentage and absolute number of working-class men and women who went to university in the 1970s increased for the first time since the 1930s.

More recent strategies like the London and National Challenge, based on the idea of school-to-school collaboration at a local level, have expanded the number of dynamic and high-performing comprehensives, often in some of the poorest areas.

Despite this, selection continues to permeate the education system overall.

Some 164 grammar schools remain, up to 36 areas have selective schools and 15 can be considered fully selective.

Contrary to the widespread myth that grammar schools promote social mobility, these schools overwhelmingly educate the advantaged and often the very affluent, with tiny numbers of children on free school meals gaining access to them.

Over the past 25 years, schools have been given greater freedom to pick and choose their pupils, a seductive tool in a system of punishing accountability, driven by league tables and Ofsted.

Some 70 per cent of schools are now their own “admissions authority,” making it hard to create balanced pupil intakes which many experts believe is one part of the answer to high-quality comprehensive education.

At the same time, liberalisation of the admission code in 2011 has given grammar schools the green light to increase their pupil numbers, damaging other non-selective schools surrounding them.

One group of particularly determined Kent parents have lobbied for the right to open up a satellite school, a full nine miles away from the original site, although the coalition backed away at the last minute from sanctioning this audacious interpretation of “school expansion.”

Other schools have tried to amend the 11-plus test to make it less class-biased or are considering lowering their pass rate to let in more children from poorer backgrounds.

However, none of these moves challenge the fundamental problem with selective education — that to divide children before puberty on the basis of so-called ability (or wealth) hinders the progress of those from less advantaged backgrounds.

It also does not make educational sense, given the exciting work that is going on in academia and within education itself on “growth mindsets” and the removal of ability labelling.

Selection is a regressive, divisive, damaging and pedagogically dull strategy that has no place in a dynamic 21st-century education system.

The sooner we phase it out, the sooner we will have a state education system that will win the hearts and minds of the public in just the way that the NHS has for 70 years.

•  Melissa Benn is a writer and campaigner and chair of Comprehensive Future. She is co-author, with Janet Downs, of the recently published ebook School Myths — And The Evidence That Blows Them Apart available from tinyurl.com/nm4fhzj.