My secondary all-boys school was a total university-entrance pressure-cooker.
At 13, pupils were divided into language based or science/maths based classes (WM's traditional academic) and many subjects, such as music, RE, art and craft, even PE simply went off the curriculum.
Social/general studies, dance and drama were catered for by after-hours school clubs if you were that way inclined; these and home economics were never on the curriculum in the first place.
Certain subjects such as history / geography (either/or), and French, were compulsory to O-level, but pupils were basically taught to optimise A-level performance in their "core stream" for university entrance.
If, like Tom (and me! ), you had no real desire to go to university, there was little careers help and a general air that you were a second-class citizen and "letting the side down".
Well, it worked for some, but not for others (including myself). I don't know how I survived it, really, looking back on it. I think a tendency to subversion and a good sense of humour helped …..