As an amount of Religious Education is compulsory in all UK schools then that is where this should be taught. Only by offering instruction on all aspects can children be said to be properly educated. Doesn't matter whether you believe in it or not. If my CoE baptised children have to sit through instruction on Hinduism, Bhuddism, Islam, Judaism and sundry other beliefs then why not Creationism ~ then, when fully informed, they will be able to make a judgement.