It is concerning that religious schools (Euphemistically termed "faith schools") have a different approach to religious education, in effect treating it as religious instruction (indoctrination) but it is even more worrying that the segregation of children according to their parents religion does not make for a cohesive society.
One only has to think of the situation in Northern Ireland, where many parents would like to send their children to integrated schools, but do not have that opportunity. Religious apartheid in schools is a factor in dividing, not unifying communities.
Religious parents will, of course, ensure that their children learn about their particular beliefs, but this is best done at Sunday school, church, synagogue, temple, mosque or other places of worship. The school RE curriculum should range across religions, beliefs and ethics in an age-appropriate way without requiring a child to affirm any doctrine.