ObCitations and Anecdotes
There have been various laws about right to education but most of them have been crap or poorly implemented. Often disabled children were segregated in "special schools" which historically had very very poor standards of education. I know someone my age (so in education 1984 to 2002ish) who has 1 GCSE from a Deaf school, he's a very bright man but his English is appalling and while he had good access to BSL, no one ever helped him make use of that in education.
In 1979 Baroness Warnock published a report that showed how poor disability education was in England and Wales. The findings got put into the 1981 Education Act where there were increased (if not foolproof) rights to a mainstream education if you were disabled.
What that meant was that many kids prior to about 1982-3 had no legal right to force councils to support them in mainstream schools. Even with that Act, My parents had to fight for me to be mainstreamed even though I only needed 1-2 hours a week of Teacher of the Deaf support and later assistance with writing and a radio aid. My parents also had to fight for me to get a statement of special educational needs which my council policies said were mandatory for all severe/profoundly deaf children. My council just claimed my speech was too good and tried to regrade my deafness as "moderately severe" which is inaccurate but still contaminates my fucking medical records to this day. I didn't need much support, mostly Deaf Awareness, 1-2 hours of Teacher of the Deaf a week (I'd been having 3 hours a week since I was a year old), and later a radio aid and some help with typing. The LEA didn't help with typing long term, that was my junior school who did that until we could argue them into it.
There have always been schools with specialist units, it could make them extra money and certainly some schools/teachers cared passionately about inclusion for at least some disabled children. In some ways a unit is the best of both worlds, enough children with a similar disability not to be The Weird Disabled Kid, while also being around nondisabled children but they are not always well integrated and my mum (a teacher of the deaf in later worklife) worked in one where they took LEA money to build deaf stuff, then quietly stole it for school stuff, making it unsuitable for the deaf children... The deaf children were very poorly integrated while the head teacher loudly bragged about them at all times. No one would hold them to account for this theft and bullshit and they didn't like my mum making noises about it.
I still only remember a handful of visibly disabled children during my education 1-2 in primary (and that was a medium sized, well regarded and inclusive place) and maybe 10 or so in secondary which was not disability friendly at all. There were several more with stuff like dyslexia but that wasn't really recognised all that much and autism/ADHD were unheard of - they were just "naughty" "weird" kids.
Legally, there was no way to enforce adjustments in education until 2002 in the UK. There was no legal right to go to university and a guy called Alan Hurst has written several books with case study after case study of disabled people refused a place at university citing everything from health and safety through to no accommodation or even "we don't have a university nurse to look after them" about someone who didn't need medical attention. You couldn't litigate against being refused a place at uni till 2002. Many universities cited the Disability Discrimination Act cos they'd promised to voluntarily do access in exchange for lobbying against actual enforceability.
Even now the school system is shit, EHCPs are awful, LEAs don't have enough money and the whole process is slow, bureaucratic, cumbersome and the litigation is limited for pre-16s and post 16 you're up against universities which are known to be horrific and nasty litigants.
