To me, it feels as though they are looking at this in totally the wrong way. The idea is that children will attend school until 6pm to help working parents. Why don't they look at it the other way around, eg, create an economy where it is normal for people (not just parents) to work flexible hours and to get part-time SKILLED jobs that pay a decent hourly rate, so children don't have to be holed up in school for longer than most office workers.
I'm so depressed at this government's lack of lateral thinking.