Donald Trump came to power as part of an anti-establishment revolt. In office, he shows no sign of easing his attacks on what he sees as opponents intent on bringing him down, whether Washington’s political elite or the nation’s news media.

“I want you all to know that we are fighting the fake news. It’s fake, phony, fake,” he said in his remarks at the annual Conservative Political Action Conference (Cpac).

“A few days ago, I called the fake news ‘the enemy of the people,’ and they are. They are the enemy of the people. Because they have no sources. They just make them up when there are none.”

What is “fake news”?

In some ways fake news is nothing new. Politicians, governments, celebrities and anyone else with a public profile have long tried to promote their own version of the truth.

But it took on a new dimension and a whole new scale in the 2016 election when small groups of individuals found they could use social media and internet algorithms to disseminate entirely invented stories to millions of voters.

Mr Trump’s anti-establishment credentials, a polarising message and a polarised electorate made a fertile audience for anyone with a conspiracy theory to spread.