Whaa, and do what? 
That's not the same as dropping out, right?
I realised someone would ask that so edited my post a bit as you were posting the question.
There is no concept of graduating high school in the UK (it's all exams, evaluations and certificates on a per-subject and per-level basis with a limited choice of subjects after about 2rd year of Secondary School) so no concept of dropping-out.
You can join the army, get married, go to college or university, get a job (with reduced minimum wage) or sign-on as unemployed (at a reduced rate of benefit)
Or you can get a load of part-time jobs, skateboard a lot, start a band and teach yourself computing like I did.
