Facebook has banned Britain First and its leaders following what it says are repeated violations of its community standards.
The social media company pointed at content posted on Britain First's page and on the pages of leaders Paul Golding and Jayda Fransen as a reason for the ban.
Facebook said both had recently been given "a written final warning" but "they have continued to post content that violates our community standards."
The social network added: "We do not do this lightly, but they have repeatedly posted content designed to incite animosity and hatred against minority groups, which disqualifies the pages from our service."
Britain First's Facebook page had two million followers globally, and the content in violation of Facebook's standards is understood to have included a photo of the group's leaders with the caption "Islamaphobic and Proud".
Other content violations included an image with a caption comparing Muslim immigrants with animals, and multiple videos posted deliberately to incite hateful comments against Muslims.
Last week, Golding, 36, and Fransen, 32, were found guilty of religiously aggravated harassment.
The ban means their group will not be permitted to set up an official Facebook page in the future.
Facebook added: "We are an open platform for all ideas and political speech goes to the heart of free expression. But political views can and should be expressed without hate.
"People can express robust and controversial opinions without needing to denigrate others on the basis of who they are.
"There are times though when legitimate political speech crosses the line and becomes hate speech designed to stir up hatred against groups in our society."
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Twitter banned the leaders last December, months prior to Facebook's crackdown.
That ban came after the group's inflammatory content was retweeted by Donald Trump, who subsequently said he was willing to apologise for apparently endorsing the group.