The silent assassin
Have pre-planned strategies to deal with lateness. When you start, tape a sign to the door saying "Quiet please: learning in progress". Place a table by the door for latecomers, rather than allowing them to trample across the room.
Set a realistic time after which pupils will be marked as late. Let everyone know what the sanction for lateness will be, then follow through in applying it every time.
Don't disrupt the flow of your lesson to deal publicly with latecomers. Instead say: "I'll speak to you in a moment", and get the class on task. Let them stew for a bit: make them wait for you, rather than responding instantly to every problem.
Make the start of your lesson unmissable. Have an exciting starter on the desks with a star prize for the winners.
When the latecomers arrive to see their classmates munching on a tasty treat, perhaps they'll consider turning up punctually next time.
Sue Cowley is an author, trainer and presenter. Her books include Guerilla Guide to Teaching (Continuum). For more information visit www.suecowley.co.uk.