A Labour MP says she has faced "very explicit" death threats after proposing a debate to decide if Britain First should be outlawed.
Louise Haigh added one individual went through all her videos on YouTube and claimed "he would not rest until I was murdered".
The MP for Sheffield Heeley also told the Commons she has been labelled a "traitor" and a "Muslim lover".
Ms Haigh suggested the threats and abuse were evidence that Britain First should be listed as a "terrorist organisation".
In November, Ms Haigh asked for a debate about whether Britain First should be proscribed as a terrorist organisation and banned from standing in democratic elections.
Speaking as MPs debated a motion to ban the neo-Nazi movement National Action, Ms Haigh said: "I'd also take this opportunity to call on the Government to give time to debate the proscription of Britain First.
"Last month I called for this debate. I didn't call for Britain First to be proscribed, I just called for this House to be given evidence and to look at the details of their paramilitary activity and their anti-democratic behaviour.
"As a result of that and the way that the media covered my call, I have received very explicit death threats.
"I have been called a traitor, I have been called a Muslim lover and on Friday an individual went through every single one of my videos on YouTube and said that he would not rest until I was murdered.
"Now, if that isn't evidence that Britain First should be proscribed as a terrorist organisation then I'm not sure what is - and I hope that the minister will give clear consideration to time in this House to debate just that."
Democratic Unionist MP Jim Shannon (Strangford) followed Ms Haigh's speech, telling her: "Everyone in this House stands with you."
He added: "It's very important you know that we're very much shoulder to shoulder with you and what you do."