I'm interested so many people say things like 'I'll let my children choose what to believe when they grow up', or 'They can decide for themselves ...'. I can't really choose what I believe, can I? Isn't there too close a connection between belief and truth?
It would be odd to say, 'I believe 6 times 9 is 53, but it's actually 54', no? That seems to be because to believe something is just to believe it's true.
What I always wanted for my children, when they grew up (as they did, eventually - all middle-aged now), was that they discover as much of the truth about the world, ethics, morality and so on, and then, of course, to believe what's true.
It wouldn't have helped (turning to OP's question) to have had them taught religion, of any sort. (It's true I used to read them bible stories - plagues of Egypt a particular favourite ('not the frogs, aargh! ... boils, eeurgh!') - but alongside other fairy stories.)
We were lucky enough to live somewhere RE wasn't at all compulsory (though it was available, different types, for people who wanted it for their children). And ime (contrary to those who post to says it's a 'good thing' to 'learn about different religions' (satanism, anyone? zoroastrianism? ...), it does good rather than harm to grow up not listening to people who take religion seriously. My children, I'll claim, are decent, fulfilled people who take their moral and societal obligations with utmost seriousness; they are also committed and hard-working parents to their children. (I suppose I would say that, hmm. I think it true, though; I believe it.)
With a bit more context, OP (and this applies to some of my grandchildren too), I think you need to play it by ear in UK - some state schools seem appropriately cautious about the whole indoctrination thing, others simply try to convert their pupils (shocking? - yes). Weigh it up. If it goes too far, make a stand. It's important that children avoid the depredations of (some) RE practitioners and teachers.