The locker was not just the place to keep your uniform it was also a place for pranks and fun.
If you were going on holiday it was recommended that you checked your locker before you went because firefighters were renowned for being pranksters and a handful of maggots thrown in the bottom of the locker soon turned into bluebottles that swarmed out when you opened it on your return.
Another trick was to brick the entrance up while you were away. Sounds like great fun to us.