The national debate over whether Britain should have a second referendum on EU membership has been set alight after Brexit architect Nigel Farage signalled he supported the idea.

Lord Mandelson was among senior Remain-backing politicians who leapt on his intervention, arguing it confirmed growing support on all sides of the debate for giving Britons another say.

But Conservatives hit out at the ex-Ukip leader as a trouble maker, accusing him of seeking to disrupt Theresa May’s Government and the Brexit negotiations.

Until now calls for a second referendum have come only from certain Remain-backing political figures, with others shying away from any suggestion they are questioning the validity of the 2016 referendum.

But Mr Farage’s bombshell comments, in which he said he was “reaching the point of thinking that we should have a second referendum” are the first time a staunch Brexiteer has come close to backing the idea.

He claimed another vote would end the “whingeing and whining and moaning” of Remainers, leading to him winning the immediate backing of businessman Arron Banks who threw millions of pounds at campaigning to leave.

Explaining his comments to The Independent, Mr Farage said: “I’m considering the possibilities that this might have to happen, and I don’t think Leavers should completely ignore the fact that it could.

“Quite a lot of us have been feeling this way for some time.”

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

On Thursday night Remain campaigners said that the arch-Brexiteer’s words could now be used as a trigger to blow open the debate on the future of EU withdrawal.

Lord Mandelson, the former Cabinet minister and European Commissioner, told The Independent: “Nigel Farage has accidentally or otherwise arrived at the truth; leaving the EU is simply too big a step with too many consequences to be left to one vote on a single day.

“To be sure about it, the public need to see the alternative before taking the irrevocable step.

“This realisation is going to grow.”

He was joined by Labour MP Chuka Umunna, leading supporter of the Open Britain campaign, who said: “For perhaps the first time in his life, Nigel Farage is making a valid point. In a democracy like ours, the British people have every right to keep an open mind about Brexit.”

Andrew Adonis, who recently called on Jeremy Corbyn to back a second referendum, took to Twitter to say “bring it on”, with the same words being used by chair of anti-Brexit organisation Best for Britain, Lord Mark Malloch.

The Liberal Democrats, who along with the Greens openly campaign for a second referendum, also waded in with their spokesman Tom Brake saying: “Support is now growing on both sides of the argument for a vote on the final deal and the choice of an exit from Brexit.”

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Mr Farage’s words were less well received among Conservative ranks, regardless of the individual’s view of Brexit.

One of most senior Tory Leavers, Bernard Jenkin, told The Independent: “He is simply being disruptive. He wants to feel important.”

Bore off back under whatever scummy rock you crawled out from under and save us all from your pathetic cries for attention Conservative MP Paul Masterton to Nigel Farage

On the other side of the party Scottish Tory MP Paul Masterton, who voted against the Government whip on the EU (withdrawal) Bill, said to Mr Farage on social media: “Maybe, just maybe, you should bore off back under whatever scummy rock you crawled out from under and save us all from your pathetic cries for attention.”

The ex-Ukip leader told The Independent that Conservatives were “terrified” of considering a second vote, because it would tear their party apart.

But he indicated that part of the problem with what had happened since the first referendum was that the Government had not been led by people who truly believed in Brexit.

He added: “The biggest irony of all is of course that the referendum was won and then the very people I’d fought for 25 years took over the reins again.”

It was on Channel 5’s The Wright Stuff, that Mr Farage said it was certain that the likes of ex-Lib Dem leader Nick Clegg, former Labour Prime Minister Tony Blair and Lord Adonis will “never, ever-ever give up” calling for a rethink.

He went on: “They will go on whingeing and whining and moaning all the way through this process. So maybe – just maybe – I’m reaching the point of thinking that we should have a second referendum on EU membership.”

He added: “If we had a second referendum on EU membership, we’d kill it off for a generation.”