Teenagers hoping to join the JFS sixth-form in September may have to wait until after exams to find out if a place becomes available.
Headteacher Rachel Fink said the school was still considering how many places to offer to its outstanding-ranked sixth-form for the next academic year.
The school offers a minimum 20 sixth-form slots to external applicants annually and this year has around 100 applicants.
Mrs Fink said that at this stage in the year “we are usually in a position to offer a significant number of conditional places.