mmurray:

For an individual parent it often comes down to not having a real choice. Note also that no matter what school your kids go to the schools is required to provide them with a weekly "act of collective worship".

Almost true, but there are private schools that don't have religious worship. Whilst many Public (= private) schools like Eton and Harrow undoubtedly do force feed their pupls Christianity, they don't have to. There are private shools like Bedales, King Alfred School, Summerhill and others where religion is not foisted on the students. Quite how a school like Eton,which gets pupils of rich parents from all over the world, manages faiths other than CoE, I don't know. They surely wouldn't want to "offend" rich arabs, Indians, and all the rest of the fee paying community, now would they? The type of muslim kid going to Eton probably pays someone else to pray 5 times a day to Mecca on his behalf!

From the information given in the OP, it seem to be a case of creeping Jesus, yet again. Sneak Him in when the kids aren't looking.