Generally brought up in asda stores of a mother turning her back fro two seconds, looks back and her little girl is missing, all doors etc. in the store are locked and the whole store is searched, they find the little girl in the toilets of the store having been taken by a polish/romanian couple (varies every time the story is told), had all her hair cut off and clothes changed in an attempt to get the little girl out of the store without anyone noticing...and so on, well its a hoax, if anyone ever tells you a story similar to this, chances are its all rubbish.
Is it the one about Princess Diana losing one of her boys in a shop and when he's found in the toilets he's got ginger hair and looks nothing like either of his parents?
i had a book (dunno where it is now......!) about urban legends....and it was fab....these things do the rounds across continents and across many generations..