full time jobs for 16 years old

The current school leaving age has been raised to 17, I believe. While it's unlikely anyone will care if you aren't in full time education, you are still legally obliged to be in some form of education (this can be a paid apprenticeship, though).

Yeah, the school leaving age is now 17.
And if anywhere is like my job at mcdonalds, if you apply for a job there at 16, they will require some form of proof of you being in education still, such as a college/6th form acceptance letter, or a letter offering you an apprenticeship (if you where doing an apprenticeship).

Not really, I didn't have to give any letter or proof that I was in school but they will most likely not accept you if you have not completed Year 11.
Maybe towards the summer they might make you start after you officially left school.

If you havent finished year 11, then you are guaranteed to have not finished school yet, so they wouldnt ask. And quite a few places wouldnt take on people under 16 anyway (well the big companies wont anyway).
But after year 11, you have to provide some form of proof that you are continuing in education for 1 year. Whether that be at college, 6th form, apprenticeship or whatever. Hence why they would want some form of proof that you are going to continue with education- such as a college/6th form acceptance letter.

That's weird, they only asked me what I was doing but never for some kind of proof.
Surely that's only if you are in the country with a student visa?

Nope, they do it for all 16 year olds. Basically because they dont want to get caught giving jobs to 16 year olds who have left school and who arent staying in education for a year when they should be. As the employer could get in trouble. And this is mcdonalds as well- a big company. So im guessing other places would do the same/similar as well.

Oh, that's nice to know.

Im guessing that way they are covering themselves and always have a backup, so if they did get caught giving a job to someone not staying in full time education when they should be, they would have the copy of the college/6th form acceptance letter as proof that they did all they could to make sure they where staying in full time education before hiring them.