Most state-maintained secondary schools that I know do indeed have open access to the sixth-form. There are, unfortunately, some state schools that also operate a selective system in relation to A-level courses by denying access to students who they feel will not achieve high grades.
These students are then faced with a choice between general national vocational qualifications or seeking another institution.
The legality of this is doubtful. It is arguable that students coming from Year 11 into Year 12 are entitled to take an A-level if the course i suitable to their needs and they have a reasonable prospect of achieving a pass.
A refusal of such access which led to the student going elsewhere could be interpreted as an unlawful permanent exclusion bearing in mind that students do not automatically come off the school roll at the end of Year 11 and can only be removed on one of the limited grounds provided by the regulations.
The likelihood of not achieving grade A in an A-level subject is not one of those grounds.
I have had knowledge of a number of such cases. Unfortunately, parents are understandably reluctant to force the issue and as a result student rights are eroded.
Stone King solicitors
13 Queen Square