But the prime minister has lost heavily in three attempts to get it through parliament. Founded in January, the party could well top the polls with the ruling Conservatives facing the humiliation of a virtual wipeout.
Speaking to Sputnik, the union leader claimed there was now a "very deep, worrying disillusionment with all parties in the United Kingdom parliament and their failure to implement the referendum result", something that would likely impact significantly on the Conservative party in the upcoming elections to the European Parliament.
Speaking in Pontefract, part of Labour MP Yvette Cooper's constituency, Mr Farage said: "A confirmatory vote, it sounds all nice and fluffy, what does it mean?"
There's been growing anxiety among Tory MPs that Brexit discussions with Labour could damage the party at the voting booths, with the European Union elections fast approaching. The collapse in support is raising pressure on May to set a date to step down.
Both Conservative and Labour camps have been damaged by their handling of Brexit. The Brexit Party led both polls comfortably.
Amid the seemingly endless stream of defeats and delays, polls are suggesting that May's Tories will bear the brunt of the blame from Brits angry and exhausted by the Brexit saga, and will be punished severely when the country goes to the ballot box next week. "We have been betrayed, not just by the Conservatives, Labour have done the same thing too".
He told the BBC that pro-EU voters will "blame us for having tried to take us out" of the bloc. "For some people this is the ultimate protest vote", he said.
He later wrote in Twitter that in a choice between a no deal exit or staying in the European Union, he would vote to leave without agreement.
Britain's Prime Minister Theresa May meets with NATO Secretary General Jens Stoltenberg (not pictured) at Downing Street, in London, Britain, May 14, 2019.
This will come after what look like being tough European elections and, by the way, during the week of President Trump's official visit to the UK.
Brexit has been delayed until October 31 as MPs failed to reach an agreement on how best to exit the EU.
If repeated in the elections on May 23, these polling figures would likely see the Greens increase their number of seats in the European parliament.
Labour, which is running second in the polls, is also being tested by the elections.
And Labour's deputy leader Tom Watson said he thought the way out of the impasse was a "confirmatory ballot" on Theresa May's agreement, saying it would be "difficult" for his party to assist in the UK's exit from the European Union without another referendum.