"Just reading the latest article on the Microsoft Schools blog, that details the following:

8.5 metres: The minimum cell space allocation for each prisoner to avoid torture or degrading treatment, as recommended by the Council of Europe “European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment”.

4 metres: The teaching space allocation for a secondary school pupil, according to BB98 (the non-statutory guidance used for school design), based on a 1,000 pupil school. The space allocation extends to a lavish 6m2 in total if you include all teaching, meeting, social and staff space (like the staffroom!)"