A Birmingham head teacher inproved exam results 12 fold by introducing isolation rooms for disruptive pupils. Basically kids are 4 warnings then they get put in the rooms during the school day for upto 3 days. The school in questioin (Ninestyles) was always known for being very rough and a bit of a dumping ground for problem pupils. When I was in school at Langley (not far from Ninestyles), 1985-87, it was widely known (or at least believed) that a Ninestyles pupil had a far better chance of going to jail than to 6th form, let alone university.
The isolation rooms sound a lot like the pindown rooms that were briefly used in the 1980s before they were banned.