The former Ukip leader made the threat as he unveiled a fresh slate of candidates for next month’s poll, which includes a former communist and an ex-commando, who has fought in Afghanistan.
The leading Brexiteer also vowed to target Labour voters in the party’s heartlands in south Wales, the midlands and the north of England, where he hopes to capitalise on Jeremy Corbyn’s equivocation over Britain’s withdrawal from the EU.
Speaking at an event in Westminster, Mr Farage said: “Leavers have to get themselves mentally prepared that there could be a second referendum.
“Rather than just saying it is never going to happen.”
He added: “It seems to me that the better the Brexit Party does on 23 May, the less chance there is of the people of this great country being insulted by being made to vote again.
“I think we can stop a second referendum.”
Mr Farage said his newly formed party was already “doing very well” with Conservative supporters, after a recent Survation poll found 40 per cent of Tory councillors were prepared to vote for it.
Setting his sights on Labour supporters, Mr Farage said: “There are five million people that voted for Jeremy Corbyn and voted for Brexit as well, and that’s going to be our task.
“I think we will go on squeezing the Conservatives and squeezing Ukip down to virtually nothing.
“We’re going to go after that Labour vote in a very big way.”
Attacking rival party Change UK as “Continuity UK”, Mr Farage said his candidates were the ones who would “revolutionise and modernise politics”.
The new list of Brexit Party candidates included Claire Fox, a former member of the Revolutionary Communist Party, who said she would be “standing in solidarity” with the Leave voters whose voices “have been traduced and trashed”.
James Glancy (a royal marine veteran), former charity boss Matthew Patten, ex-nurse Christina Jordan and smoked salmon producer Lance Foreman are also running.
Change UK, a rebel alliance of former Tory and Labour MPs, unveiled their candidates for the upcoming polls at an event in Bristol.
Top names included journalist Rachel Johnson, sister of former foreign secretary and Brexiteer Boris Johnson, former Tory health minister Stephen Dorrell and ex-BBC Newsnight presenter Gavin Esler.
Originally known as the Independent Group, the new party was formed when 11 Labour and Tory MPs dramatically resigned from their parties in protest over Brexit and Labour’s handling of antisemitism complaints.
Interim leader Heidi Allen said it was a “Remain alliance” and it would throw its weight behind fighting for a second Brexit referendum.
The Independent has been calling for a Final Say vote on Brexit since last summer. The campaign has been backed by more than a million people.
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