I haven't know that kindergartens have exactly the same role as nurseries in the UK. I've been thinking that kindergartens are something like pre-schools, and nurseries have to do with baby minders. In Japan, there's a special kind of institute called "hoiku-en", where children spend a whole daytime with several baby minders. It means that one can't use hoiku-en unless both parents are working. Children with his mother or father usually staying home, and being taken care by she or her, have to go to kindergartens. The point is, kindergartens generally close before 3 o'clock, so parents having daytime jobs can't use them, and if they weren't allowed to let children enroll any hoiku-en --- it's often the case when there's more children than the enrollment limit of hoiku-en in the region --- they have to quit their jobs.