The clock strikes 11am and boys spill out of classrooms into the corridor to move on to their next lesson.
There is no noise and no jostling. Instead they walk in an orderly manner, heads bowed respectfully and eyes downcast to avoid my gaze. The boys, all aged between 13 and 19, are dressed in ankle-length white salwar kameez and white skullcaps.
Their feet are bare. For this is no ordinary school. This is Darul Uloom, a Muslim madrassa or religious school, set in the pretty Kent village of Chislehurst. It is one of 166 Muslim schools in Britain today.
Of those, 26 are Darul Ulooms, religious seminaries rooted in the Islamic orthodoxy of sharia. According to an ICM poll, almost half of British Muslims wish to send their children to Muslim-only schools.