Your multiple postings are interesting. This is something you have a real bee in your bonnet about isn't it?
Until the early 1970's 15-year-olds could leave school and work full time without having to sit school exams.
In the 1970's this country began to lose jobs and so since then the government has regularly upped the school-leaving age, to mask the terribly high unemployment figures, and to try and force the creation of a skilled workforce - most British workers before the 1970's were unskilled.
As a person who has taught for thirty years, I would be delighted to see 12 -year -olds working if they didn't want to be in school. Many kids learn little in school after this age.
But the current law says they can't. So your job as a citizen (remember all those PSHE lessons?) is to badger members of parliament to change the law, and to use your vote when you are 18 to support your views. This will be a useful channel for your frustration, whereas sounding off in this forum will get you nowhere.