Facebook has removed the pages of the anti-Islamic group Britain First and its leaders.
The social media company said the group had repeatedly violated its community standards.
Earlier this month, Britain First's leader and deputy leader, Paul Golding and Jayda Fransen, were jailed after being found guilty of religiously aggravated harassment.
More than two million people had liked the group's Facebook page.
The pages of Paul Golding and Jayda Fransen also had large followings.
Facebook says the decision to remove the pages was made after Britain First had ignored a final warning about the posting of material that broke its community standards.
The group will not be allowed to set up a replacement page.
It is understood that Facebook judged the videos and photos to be designed to incite hatred against Muslims.
Prime Minister Theresa May told the House of Commons that she welcomed the move and hoped other tech companies would follow.
London's mayor, Sadiq Khan has also issued a statement.
"Britain First is a vile and hate-fuelled group," he said.
"Their sick intentions to incite hatred within our society via social media are reprehensible, and Facebook's decision to remove their content is welcome."
It is understood the offending posts included:
- a photo of the group's leaders with the caption "Islamophobic and Proud"
- a caption comparing Muslim immigrants with animals
- multiple videos posted deliberately to incite hateful comments against Muslims
In a blog, Facebook said it was an open platform for all ideas but that political views 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 has been pressure for some time on Facebook to act against Britain First.
The social media company says it removes hate speech against people based on their race, religion, gender and other characteristics.
Its community standards document states: "Organisations and people dedicated to promoting hatred against these protected groups are not allowed a presence on Facebook."
Twitter suspended the accounts of Paul Golding and Jayda Fransen, after its new anti-abuse rules came into force last December.
US President Donald Trump had retweeted anti-Islamic videos posted by Fransen the previous month.