They've just announced closing schools in Finland and they are making some exceptions - 1-3rd graders (so up to 10 years old children, who most need care during the day) whose parents are essential workers will get school arranged specially for them so their parents can go to work. (Daycares are also staying open but everyone who can care for their children at home are being encouraged to do so)
This is surely the way for the UK to go, the people that are really needed can still go to work but most children won't be in schools and then spreading their germs everywhere. All social things like pools and libraries and clubs are being closed too so children aren't likely to be out and about otherwise.