大象传媒

President Trump continues to criticise the NFL over players refusing to stand for the national anthem. He's angry at what he says is "disrespect" for the flag; he's called for them to be "fired". Some players have been getting down on one knee during the playing of the anthem. Their protest is at what they see as racial injustice in their home nation. Our reporter in Washington, Anthony Zurcher, talks us through the 100-year-history of the Star-Spangled Banner.

(Picture: Members of the Dallas Cowboys link arms before the National Anthem Credit: Christian Petersen/Getty Images