Primary school not allowed ladders due to health and safety. Therefore staff use chairs to reach up when 'working at heights'.
There is nothing in health and safety law that prevents primary schools from using step ladders in classrooms.
A properly designed stepstool or stepladder is often going to be the sensible and practical option for carrying out tasks that involve working at height for a short time – and schools are no exception. It’s certainly a safer option than standing on a chair!