NIGEL Farage has sparked outrage among Labour politicians after linking the widower of murdered MP Jo Cox to "extremists" hours after the Berlin terrorist attack.

The former Ukip leader laid into Brendan Cox after he questioned the right-wing politician's Twitter claim that the atrocity in the German capital was a result of Chancellor Angela Merkel's decision to allow migrants into the country.

Mr Cox, whose wife was murdered by neo-Nazi Thomas Mair in June, had replied saying that "blaming politicians for the actions of extremists" was a "slippery slope".

Hours later Mr Farage went on LBC radio and said: "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 very undemocratic means."

This prompted angry replies from former colleagues of the Batley and Spen MP in Westminster.

Chris Bryant, the Rhondda MP and former shadow Commons leader, said: "The sheer nastiness of Farage sometimes takes my breath away."

Chesterfield MP Toby Perkins added: "When your entire career has been built on hate, not hope, it perhaps shouldn't shock me, but Farage still sinks lower than I'd have believed."

Tracy Brabin, who won the Batley and Spen by-election after Mrs Cox's murder, said: "Beggars belief... A new low for Farage."

Mr Farage had taken to social media this morning in the wake of the Berlin outrage, which left at least 12 dead at a Christmas market, saying: "Terrible news from Berlin but no surprise. Events like these will be the Merkel legacy."

The comment prompted hundreds of retweets and replies, including from Mr Cox, whose Labour MP wife was shot and stabbed only days before June's EU referendum.

Before Mr Farage's Twitter comment, Mr Cox had tweeted: "Terrible news from Berlin. We must pull together to drive out hate in all its forms.

"Far right & Islamist extremists share same hate driven psychology, intolerance towards difference & tendency to violence. We must defeat both."

Mr Farage also told LBC: "I'm sorry Mr Cox, it is time people started to take responsibility for what's happened. Mrs Merkel had directly caused a whole number of social and terrorist problems in Germany, it's about time we confronted that truth."

Mrs Merkel has shifted her policy towards refugees and migrants to the right in recent weeks, including a speech in which she suggested stemming the number entering Germany and restricting the use of face veils.

Germany admitted almost 900,000 migrants in 2015 after deciding to allow in those who had made it to Hungary.

Although the numbers has dropped sharply in 2016, Mrs Merkel's CDU party has suffered internal strife and a string of poor election results.

Mair, who killed 41-year-old mother-of-two Mrs Cox as she arrived to hold a surgery in Birstall, was handed a whole life sentence in November.

Mair, 53, shouted "Britain first" as he fired three shots at Remain campaigner Mrs Cox and stabbed her 15 times on the afternoon of June 16.

After Mair, of Birstall, was jailed, Mr Cox said he had committed the "most incompetent and self-defeating" act of terrorism.

In a statement, Hope Not Hate said: "We are aware of a serious and potentially libellous statement made about Hope Not Hate by Nigel Farage on LBC radio this morning.

"We have no idea on what Mr Farage bases his outrageous comments. Hope Not Hate has a proud history of campaigning against extremism and hatred.

"We will not be making any further comment until we have had the opportunity to consult with our lawyers."

The group later said its lawyer had asked Mr Farage to apologise or face legal action.

In an appeal for funds on its website entitled "Help us take Nigel Farage to court", Hope Not Hate said: "This morning, on LBC radio, former Ukip leader Nigel Farage launched an outrageous attack on us, on Brendan Cox, husband of murdered MP Jo Cox, and by association on everyone who believes in Hope not Hate.

"Our lawyer has just sent Farage a letter demanding he retracts and publicly apologises or we will begin legal proceedings against him."