Queen's School in Wisbech has installed CCTV cameras in the toilets to keep an eye on pupils.
The idea is to discourage them from skipping lessons by hiding out in the loos and to stop younger pupils feeling threatened by older children.
The cameras can only see what's going on outside the cubicles, but just outside the loos there's an attendant watching out for any problems.
And if there's any sign of trouble they go straight in to sort it out.
Doing up the toilets cost the school around £100,000 and it's hoped pupils now feel safer spending a penny.