re: Dear Conservative govt
There was a time when I would have agreed with you.
However, I think there is a place in schools for "cultural studies" and a very big part of some cultures is their religion. Knowing about religions can be of use when making friends and interacting with colleagues, for example. Or, if you want an extreme example (which I'll admit is a little tenuous and silly), if you happen to visit an Islamic country* you will at least know that drinking, eating pig meat, public displays of affection or nudity and calling teddy bears "Mohammed" is likely to be frowned upon.
I should point out that I don't think children should be taught to believe in any particular religion (even by their parents but that's another matter), but I think knowledge of religions, even if it's just for historical reasons, has a valid place on the curriculum.
For the record I'm an atheist.
*easy example, I'm sure people can think of ones for bible-belt US and similar.