did you know?

.. when I did the refs' course some years ago, we were told that half-time was officially FIVE minutes. Obviously we all queried this, and were told that refs would start a five minute timing once everyone was in the dressing rooms.

I was sceptical at the time. I wonder if the laws have been altered in recent years, or if there's just been a tacit understanding between officials and managers/players that they want about 15 mins?