Capped at 4 ? damn. We don't have a cap here. I've worked with people who had to give 16 weeks notice, but they also get 16 weeks redundancy pay so swings and roundabouts.
My Mum switched universities and had to give 8+n weeks notice, with n being the remaining number of weeks until the end of the sixth semester (roughly the end of July). However, if she were to be let go she'd get something like a year's redundancy pay (not that heads of computing faculties will be redundant any time soon).