Sentence:  The centrepiece of her work was a weekly column that could brim with venom . . . . Cherie Blair, Geri Halliwell, Sarah Ferguson, Victoria Beckham and Princess Diana all found themselves the subjects of Lee-Potter's <WSD>poison pen</WSD>. 
Meaning of the word marked with <WSD> tags:  A manner, means, or tone of expression had by a written work, characterized by spitefulness, defamation, and/or intimidation directed toward a person, organization, or point of view.