The European Union’s (EU) chief Brexit negotiator has invited leading anti-Brexit Labour, Liberal Democrat, and Tory campaigners to Brussels for talks.

Veteran Tory MP Ken Clarke, former Lib Dem leader Nick Clegg, and Labour Lord Andrew Adonis described themselves as “the rebels” as they arrived to meet Michel Barnier Monday.

They were dubbed “an unholy Trinity going down and desperate to undermine the democratic Brexit vote” by Nigel Farage, the former UKIP leader, after the leading anti-Brexit agitators arrived in the European capital.

“Especially so, as Clegg has no electoral mandate. That Michel Barnier is even meeting them shows those in Brussels cannot be trusted in these negotiations at all,” Mr. Farage added.

“We’re going to see Michel Barnier and a few other people in the European Commission,” Mr. Clegg, who lost his Sheffield Hallam seat to Jeremy Corbyn-supporting Labour candidate Jared O’Mara, told the BBC as he walked into an EU building.

“Are you here to stop Brexit?” he was asked. Laughing, Mr. Clegg replied: “If only it were that easy. We’re here to just get a better understanding of what’s going on in the talks.”

Mr. Clegg has authored a book titled How to Stop Brexit, which insists “there is nothing remotely inevitable about Brexit” and claims that “it would certainly be the best thing for Britain” if the referendum result were reversed.

Mr. Clarke jokingly told reporters that they were there to “talk about cricket”.

“Ken, are you allowed to be here because this isn’t government policy, is it?” asked the BBC reporter. “Is government policy not visiting Brussels?” responded the former Tory home secretary and chancellor of the exchequer.

Back in 1996, Mr. Clarke infamously told the International Currency Review: “I look forward to the day when the Westminster Parliament is just a Council Chamber in Europe.”

Lord Adonis, meanwhile – a Labour minister under Tony Blair – back in July compared Brexit to appeasing Adolf Hitler in the 1930s and claimed that Britain is in “serious danger” after voting to leave the bloc.

Mr. Barnier has met Labour leader Jeremy Corbyn and Shadow Brexit Minister Keir Starmer twice, as well as Scottish First Minister Nicola Sturgeon and First Minister of Wales Carwyn Jones.

Tony Blair also sparked fury by meeting European Commission President Jean-Claude Juncker in Brussels when negotiators were locked in Brexit talks.