On The Buses - "You're late again, Butler!"

In On The Buses Inspector Blake was constantly haranguing Butler & Harper for being "Late". He rarely meant that they had turned up for work late - he meant either that they were late leaving the depot or that they were late returning.
Sometimes Blakey threatens to write out a full report on the fact that Butler's bus was late.
I know now, and I suppose most people know now, that no bus driver in history has ever got into trouble for being late on his route.

But he could get into serious trouble for being too early!

It is the opposite of what one might expect, and that is probably why the writers changed it.