From the 2011-12 academic year, all classes will start on the hour and finish at ten minutes to the hour e.g. 9:00-9:50. There may be some old timetables still around suggesting that some classes start at ten minutes past the hour. These timetables are innaccurate and should be disposed of; all classes start on the hour.
In previous years classes have started on the hour at 9:00 and 10:00, but then later classes started at ten past with 10 minutes allowed for change over between classes. This has been confusing particularly for students.
Hopefully, the new, consistent start times throughout the day and the 10 minutes change over between classes will make things much simpler for staff and students.