Knock, knock!Who's there?A Newsround presenter.A Newsround presenter who?A Newsround presenter who is trying to tell a joke... This video can not be played To play this video you need to enable ...

Former Newsround presenters look back on 50 years of BBC's kids' news show ...

It was presented by either Newsround presenters, Adam, Lizzie, Thalia or Rachel. It aired between 2002 and 2005. It was discontinued due to poor ratings.