Trump turmoil: White House seniors deny writing NYT op-ed

Donald Trump has gone on the warpath as he tries to find out who wrote an anonymous column in the New York Times claiming senior officials are deliberately undermining his presidency. The Washington Post quotes an unnamed insider saying Mr Trump reacted to the article with volcanic rage. The person told the Post it won't be easy to find out who was responsible because there are so many candidates. Vice-president Mike Pence and Defence Secretary Jim Matthis have denied it was them. We talk to Washington DC correspondent Simon Marks.