The debate about Brexit in the UK has gotten to a “bonkers” phase, with people more concerned about the purity of their position than any benefits that might accrue from leaving the EU, the Irish Congress of Trade Unions (Ictu) biennial congress has been told.

Matt Frei, Europe editor with Channel 4, said there were reasons for believing that the rise of populist politics in Europe and the US may have peaked.

Frei, a former Washington correspondent with British broadcaster, told of interviewing the then businessman Donald Trump in Trump Tower in New York in 2011, and laughing when told by Mr Trump that if he decided to run for president he would use the slogan “make America great again”.

His first thought had been “that’s not going to work”.

Since then, he said, Mr Trump had become the US president, the right-wing AfD in Germany had become the official opposition, Marine Le Pen had become a serious contender for the presidency of France, populist and dangerous politicians had risen to power in Italy and Spain, and Viktor Orban in Hungary had turned his party into an anti-immigrant, anti-Islam party with hints of anti-Semitism.

Frei said these developments all had their national characteristics, but had a common strain of being based on false narratives and a purported battle of the people against the elites. “The power of populism to tell stories that are not necessarily based on the truth is extraordinary.”

Traitors

He said the situation in the UK was particularly toxic, with newspapers describing the judiciary and members of parliament as traitors. The years since the Brexit referendum had been a clash between parliamentary democracy and democracy by plebiscite, and had now reached a “bonkers” stage where people were focused on the purity of their position.

He said it was “ almost like a religious debate” from the 14th century, involving a macho competition about who can deliver the most pure form of something that most of the leaders of the Conservative party do not actually believe in.

“They don’t even talk about the benefits [of Brexit] now. It’s like going to the dentist. It won’t be as bad as you think,” Frei said.