A row has broken out over plans to end the traditional early-morning start to the school day.
German children are the early risers of Europe, starting school between 7.30am and 8am. Some schools even require lessons to begin at 7am. By contrast children in Britain, France and Spain start at 8.30am or 9am. German children finish at 1pm or 2pm, depending on age.
Researchers have debunked the idea that an early start is beneficial. Juergen Zulley, head of the Centre for Medical Research into Sleep at the University of Regensburg, said: "It would make more sense to start school at 9am. This time fits children's biological rhythms better, and creativity is at its highest between 10am and 11am." Children who may spend late evenings in front of the television or computer screen are still rubbing the sleep from their eyes in the early morning, rather than concentrating on lessons.
Research at LuebeckUniversity shows that primary pupils require 10 to 12 hours of sleep a night, and teenagers need eight or nine hours. But the early start makes it unlikely that children get enough rest, particularly as 20 per cent of German children are thought to have sleep problems.
Steffen Reiche, Brandenburg's education minister, and Gabriele Behler, schools minister in Nort Rhine-Westfalia, believe that starting school later would benefit pupils. "The tendency to rise early seems to me a German peculiarity and one which I don't particularly value," said Mr Reiche. "Personally, I'm much happier when I've had enough sleep."
Brandenburg is already trying to stop lessons starting before 7.30 am, "without being too draconian about it", but a 9am start for schools may be a pipe-dream.
This debate has touched a nerve. Some experts are also calling for a full day's schooling from nine until four - something that teachers, who value their free afternoons, do not relish. And conservative politicians insist that half-day school is conducive to family life - a point belied by generations of latch-key children.
While parents quite like the idea of children staying at school for the afternoon, rather than coming home by lunch-time, few support the later start simply because work usually starts around 8.30am in Germany and working parents would have trouble taking their children to school.
In a poll carried out by the weekly Focus magazine, 65 per cent of participants rejected a 9am start and only 24 per cent were in favour. A survey by the polling institute Emnid found that two-thirds poured scorn on the research into sleep patterns.