If children are to be taught ABOUT religion, it should be called something like Comparative Religions and include non Abrahamitic religions and paganism, so that students get a truly detached view of what religion is.

It would be extremely useful, for example, to study the parallels between the birth and resurrection stories in Christianity and in Ancient Egyptian theology (Isis and Horus/Osiris), Mithraism, etc. Old Testament tales of slaughter should also be taught in all their gore, so that the students have a clear idea of what a war-god sounds like, and these myths too should be compared to similar ones in other primitive religions, war-like religions. No kid should leave school with the ridiculous belief that any religion is a 'religion of peace.'

But I'm guessing schools in both the UK and the US are far from this view of the subject.