Local authority-maintained schools have been given the power to vary their school day as they see fit.
The changes, which came into effect at the beginning of September, give them the same powers to alter lunch times and adjust the length of the school day that academies and other non-local authority controlled schools have.
Aimed at reducing the amount of bureaucratic red tape, the new measures allow all state schools to control their own timetables, whereas previously it could take up to three months if they simply wanted to change their lunchtime by five minutes.
Schools Minister Nick Gibb said the government wanted to give schools more power to run themselves as they wished.
"It shouldn't be central government or detailed regulation that determines the time a school day starts or the length of the school lunch break," he said.
Supporting the move, Russell Hobby, general secretary of the NAHT union, commented that as long as changes were carefully planned, longer school days could be a powerful tool in improving schools.