Classy

Harriet Harman Update, 15.10 BST:
"Although [Harman] dropped the word 'class' from the text of her speech when it was delivered, she later denied on the BBC's World at One that there was any taboo about using the word." (http://news.bbc.co.uk/1/hi/uk_politics/7607895.stm ).
In that case, why was the word omitted from the text?