JFS is to drop its accelerated academic programme for first-year students from September.
Until now, they were taught in tutor groups for all subjects, except Jewish studies, Hebrew and PE for which they were divided into sets.
The 40 per cent of most able students went into its accelerated stream.
From September, first-years will go into sets for English and maths in addition to the other three subjects. But for remaining classes, they will be "mixed according to a range of criteria", executive headteacher Debby Lipkin and headteacher Simon Appleman told parents.
The new arrangements, they said, would "enhance progress as well as provide support for those who need it most".