I think you need to go back to Russell group found in 1994 as the group of 24 Public research unis. These comprise mainly of the old “masonry ” universities in existence before 19th century (e.g. oxbridge, Durham, St. Andrews, Edinburgh, Dublin etc ) plus what are known as the “red Brick” uni (Red Brick refers to the original 9 universities in industrial cities founded in 19th century, but later also included universities built post Ww1 which at first we’re known as “glass). These terms genuinely do refer to building materials used- bricks being cheaper than stone etc.
These were all universities that existed long before the 1992 Education Act which allowed polytechnics to become full universities. And this is where the idea of not all universities being the same came from
Polys could not award their own degrees, a lot did not offer “honours” degrees but “ordinary” degrees at most , but also focused on diplomas etc. This difference was known as the “binary divide” and grew massively as more polys opened during the 1960s.
when I applied for Uni in early 80’s you had a choice of Uni or poly. I choose 3 Unis and 2 polys as my backups in my UCAS application, which was pretty standard then for comprehensive schools. Poly entrance grades were typically slightly lower
Universities were entirely different than Polys. Universities offered Academic courses being taught by the academic staff (sometimes really badly🙄🤣) and undertook academic research with funding they received as a main income and activity stream. They were in effect institutes of research that awarded degrees on the side.
Polys were more like tertiary level FE Colleges- courses taught by lecturers where that was usually their main job objectives - arguably giving better quality of teaching. . The courses were less acedemic, more practical and offfered completely different syllabus. often they had strong links into industry, businesses etc. and most research done by PolyS were in STEM subjects with a direct link to businesses. As a chemistry grad for instance- university gave me a BSc (hons) in pure chemistry - very much the theory and just a few modules of application. A poly ordinary degree I applied for would have had way more bench work /lab time and I would have been trained on analytical techniques in more detail to be able to hit the ground running after graduation to work in a laboratory.
I personally think it was a backward step to do away with polys and convert them to unis. But there was money and funding at play. Polys offered a
lot to a lot of people who didn’t want to do something very academic and theoretical. It was much more a accessible and equipped students strongly with skills they need for work through the polys links to industry.
before 1992 , only about 10% of population went to actual University. So, it tells you that they were pretty elitist institutes . There was snobbery around it. And that persists today in the continuation of “Russell group”. Probably the people who went to “Masonry” universities consider them to be prestigious - but in reality it depends on what degree you’re doing.