How ridiculous can this government get?
Obviously no-one in government has had to teach a class of disillusioned 15 year-olds.
I say let them leave on their 14th birthday if that's what they want and give them a credit for the year in which they leave plus the rest that would be required to complete A-Levels assuming no repeated years.
No dole, or whatever they are calling it this year, until they are 21. No money at all under any title.
At any time after they leave school, yes, anytime, they may return and complete their education at no cost to themselves.
This simultaneously removes the worst offenders from the classes and populates the classes with more mature individuals who know why they are there and will assist the teacher in keeping order and might explain the facts of life to the younger ones.
I know of one girl who did just that, left at 14, got a job as an international model, got married, had a baby, and then real life hit. So she went back to Mummy & Daddy, older and wiser, lived at home and completed her education to degree level. Of course this wasn't in the UK, and she would do it all over again. It was a wake-up call that taught her about life, what she wanted out of it and what she would have to do to get it. And she did.
In her class there were married people, people with kids, people with intentions and it made the class-room a much happier place. It was also much better for any kids who were either very brainy therefore ahead of where they should be at their age, or somewhat backward and repeating years. They no longer stood out as different and the adults stopped the bullying at source in their own ways, much more effective than anything a teacher could legally contemplate.
