What is Britain First?
Britain First is a far-right nationalist U.K organization that exists largely to protest Muslim immigration to the country, which it tends to characterize as an "invasion."
"Britain First stands opposed to all alien and destructive political or religious doctrines, including Marxism, Liberalism, Fascism, National Socialism, Political Correctness, Euro Federalism and Islam," reads its charter. "Britain First is a movement of British patriotism and democracy."
However, are often referred to as "fascists" in the British press. It is best known for its robust social media presence and occasionally violent behavior.
And why are we talking about them?
Because President Trump. Jayda Fransen, the deputy leader of Britain First, had tweeted a series of videos where Islamic fundamentalists commit various heinous acts, including one of an ISIS preacher smashing a statue of the Virgin Mary.
Is Britain First big in the U.K.?
No, and Fransen herself ran afoul of the nation's relatively strict hate-speech laws last year when she yelled at a woman wearing a hijab during a "Christian patrol" of a predominantly Muslim neighborhood.
Britain First has run candidates for office in the U.K. but is not represented in the country's parliament or at the local level. It is considered a fringe movement that is kept at arm's length by other right-wing parties in the country, such as UKIP. When Mr. Trump retweeted Fransen, a British editor at conspiracy theorist Alex Jones' far-right and pro-Trump InfoWars website criticized the president.
Muslims are the primary target of Britain First's ire, but they're not the only one. Fransen herself is not a big fan of Irish republicans, and according to The Independent, Britain First was founded in 2011 by Jim Dowson, who has ties to Protestant militants in Northern Ireland.
Dowson would later leave Britain First because he thought it had become too radical in its anti-Muslim stance, and the party is now run by Paul Golding, who had earlier been expelled from the far-right British National Party for extremism. In 2016, Golding ran for Mayor of London, finished in eighth place, and turned his back during the victory speech of Sadiq Khan, the city's first Muslim mayor.
Golding was convicted of assault in an unrelated incident by a British court earlier this month.
How is the U.K. reacting to Mr. Trump's retweets?
Prime Minister Theresa May, for one, is not happy.
"Britain First seeks to divide communities in their use of hateful narratives, which pedal lies and stoke tensions," the spokesman for May, a Conservative, said in a statement Wednesday. "This causes anxiety to law abiding people. British people overwhelmingly reject the prejudiced rhetoric of the far-right, which is the antithesis of the values that this country represents -- decency, tolerance and respect. It is wrong for the president to have done this."
Has Britain First ever made an appearance in American politics before?
Yes, according to CNN's Andrew Kaczynski, who noted that Britain First created the video shared by Republican Alabama Senate candidate Roy Moore that falsely said that President Obama is a Muslim.