Nigel Farage said the United Kingdom should "have one last stab" and attempted to negotiate a Canada-style trade deal with the EU.
Speaking on his LBC show, he said: "If that doesn't happen we will walk away and they will probably get much more badly hurt by this than we will".
Brexit Secretary Dominic Raab said securing a deal was still "the most likely outcome" - but added making alternative arrangements was the "responsible" thing to do.
"The vote was a political debate".
U.S. committed to expel Iran and its allied militias out of Syria
The Trump administration is ending funding for Syria stabilization projects as it moves to extricate itself from the conflict. Ambassador to Turkey James Jeffrey was named U.S. special representative to Syria on August 17.
"And that's because of the way the politicians have behaved".
Mr Farage's return is another potential headache for Mrs May, who is already facing bitter opposition to her Chequers proposals from a...
The former Ukip leader will tour the United Kingdom with the Leave Means Leave group to challenge the Prime Minister's Chequers "betrayal".
Writing in the British Daily Telegraph, he said he had made a decision to act as it had become clear the "political class in Westminster" was determined to frustrate the 2016 referendum vote to leave the European Union.
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Jones' Twitter account was suspended for one week - a move that the platform was late in the game for after other services had already removed the far-right hosts' content.
The former UKIP leader wrote: "Theresa the Appeaser has produced a set of ideas that are nothing more than a cowardly sell-out".
Mr Farage wrote: "Over the last few months, and particularly since the Chequers betrayal, scores of people have stopped me in the street to ask: 'When are you coming back?' With all this in mind, now is the time for action", he said.
"The time has come to teach them a lesson - one that they will never forget".
He added: "Well now you have your answer: I'm back".
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Mateo, born prematurely in December 2017, spent the first five months of his life in hospital. City broke the 100-point barrier for the first time on route to their first title since 2014.