teachers work under slave labour conditions.

There are two types of slave labor.

1. Working for low wages.

2 Working long hours.

Teachers work longer hours than pre industrial revolution. see link.
The average day was around 8 hours where as teachers days are 8.30 to 5.30
plus 8 hours at home per week and a Saturday or Sunday. 60 hours a week minimum.

http://groups.csail.mit.edu/mac/users/rauch/worktime/hours_workweek.html

Teachers are nothing more than forced labor workers due the increase demands placed on them by the national curriculum. They have to work extremely long hours, this amounts to slave labor.
They have no time for family life or entertainment.

Many teachers are leaving or trying to convert their positions to part time with salary sacrifice.
It's at the point where teaching is not a tenable profession for most of the graduates unless they have a masochistic personality. Not really the type of people I would want teaching my kids.