The hours are wrong. All full time teachers I know end up doing about 3-5 hours a day on top of their 8-5pm hours, lesson planning, marking, etc.
I'm presuming the teachers you know are relatively new to the job?
I'd question their ability at being able to organise and plan their work efficiently if they were spending until 10 pm EVERY night after a few years in the same role. We all know that many people like to exaggerate how hard they actually work. Saying that, I also know teachers and they openly admit to marking work during lessons after setting pupils a task.

. There are some subjects and positions which don't require long hours, but many do. My wife is Director of English at an 11-18 yrs boys school. She starts work soon after 7am and doesn't usually finish until 5pm, regularly with no stop for lunch. Almost every day she will then do an additional 2-3 hours work in the evening, and also at the weekend. This isn't because she isn't organised or good at her job, she is, it is because of the amount of work she has to do to make sure her department, and the school, keep up with Gove's ever changing policies and procedures.
