The anti-fascism charity Hope not Hate has launched legal action against Nigel Farage after he accused the organisation, which campaigns for racial and religious harmony, of pursuing “violent and undemocratic means”.

A libel claim was filed in the high court by the charity on Friday for up to £100,000, in damages for reputational harm along with an injunction to restrain the former Ukip leader from repeating the remarks.

The timing of the legal proceedings, which was financed by 14,000 people who responded to a crowdfunding appeal, aims to stop Farage and his rightwing support base from making such statements in the runup to the general election.

Nick Lowles, chief executive of Hope not Hate, said: “This case is not about money. It’s about Hope not Hate saying no more to Nigel Farage’s fake news. We are an avowedly peaceful organisation and Nigel Farage’s lies are deeply damaging to the vital work we do bringing communities together across cultural and religious divides. As the election campaign gets under way, we are putting Nigel Farage and his supporters on notice that we will not tolerate being smeared with the ‘violent’ tag. We will not allow them to peddle this lie to the people of Britain.”

We know that this case won’t hurt Nigel Farage financially. This is not about money, this is about telling the truth Nick Lowles, Hope not Hate

The comments were made by Farage on the Nick Ferrari at Breakfast programme on LBC radio last December, a day after the terrorist attack on a Christmas market in Berlin. Earlier, shortly after news of the attack emerged, the 53-year-old MEP had tweeted: “Terrible news from Berlin but no surprise. Events like these will be the Merkel legacy.”

Brendan Cox, the husband of murdered MP Jo Cox, responded on Twitter: “@Nigel_Farage blaming politicians for the actions of extremists? That’s a slippery slope Nigel.” The following day, 20 December, Farage was asked about Cox’s tweet on the radio show, which has an audience of one million listeners. Farage responded: “Yes, well of course he would know more about extremists than me, Mr Cox. He backs organisations like Hope not Hate, who masquerade as being lovely and peaceful, but actually pursue violent and undemocratic means.”

His remarks were picked up across the mainstream media and the charity received a barrage of abuse on social media from rightwing supporters who accused it of extremism, fascism and violence. A request from Hope not Hate to Farage to apologise and retract his statement was ignored, leaving the charity to issue legal action. As the high court requests claimants to put a sum on the damages claim, the organisation has said it is seeking between £50,000 and £100,000.

Lowles believes that Farage’s refusal to apologise is based on the fact that his charity has “shone the spotlight” on Ukip and campaigned to stop Farage being elected to the South Thanet parliamentary seat at the 2015 election. On Thursday, Farage announced that he would not stand in the general election on 8 June, although he admitted he had been tempted to contest former Ukip MP Douglas Carswell’s Clacton seat.

Lowles said: “Nigel Farage knows that smears and lies take hold if repeated enough times. It’s time to take a stand against liars who bully and shout down those who peacefully disagree with them.

“We asked Nigel Farage to retract and apologise for his remarks attributing violence to HnH and linking the husband of Jo Cox to extremism. All Nigel Farage had to do was say sorry.”

Court documents laying out the basis for legal action describe Farage as an “extremely influential figure” who was named “Briton of the Year” by the Times in 2014. In November 2016, Donald Trump, after becoming president-elect, suggested via Twitter that the UK government should name Farage as British ambassador to the United States.

Lowles said: “We know that losing this case won’t hurt Nigel Farage financially. He is a millionaire former City stockbroker with a personal backer worth £100m and a billionaire cheerleader in the White House. This case is not about money – this is about telling the truth.”

The court documents describe the charity as being set up “to investigate, expose and campaign against the activities of the far right and other promoters of hate in Britain and internationally” and “promoting knowledge and mutual understanding between different racial and/or religious groups”.