Speaking to fellow GB News host Dan Wootton, Mr Farage said: “If we really are going to completely sell out in every way towards a Swiss-style deal or whatever else it may be.
“If we get to that point, I would have no choice but to do something.”
He added: “I do not want to do this again but, I’ll make it very clear, if as in 2019 under Theresa May when I had my first comeback, if I have to really look like a modern-day [Frank] Sinatra and comeback again then if they betray Brexit I will be left with no other option.
“I want to say this very clearly to Conservative Party leaders and thinkers, if I have to comeback and do this again, at the next general election you won’t lose, you’ll be obliterated, literally obliterated.”
Mr Farage compared the potential Brexit-induced Tory collapse to when Labour replaced the Liberal Party in opposition after the First World War.
JUST IN: Swiss-style Brexit deal rejected as ‘ridiculous notion’ after Sunak rejects idea – poll
Allies of the former Brexit Party leader have also indicated that recent decisions taken by the Government could prompt Mr Farage to return to the frontline.
Ex-UKIP economy spokesperson Patrick O’Flynn suggested a Brexit pivot would “delight” Mr Farage.
Writing for the Spectator, Mr O’Flynn said: “The very big slice of public opinion that is resolutely pro-Brexit and always looks down on chicanery aimed at undermining it constitutes by far the majority of conceivable Tory voters in 2024. Indeed, Nigel Farage is already licking his lips.”
Former Brexit Party MEP Alex Phillips told Express.co.uk earlier this month: “The way the Conservatives are poling right now, they will be extremely worried about haemorrhaging votes as it is very clear the Tory Party is not as popular with their grassroots and they are losing shed loads in the Red Wall.”
Lance Forman, who defected from the Brexit Party to the Conservative Party ahead of the 2019 General Election, added: “A party which was adamant about scrapping EU rules and controlling borders would win support across the political spectrum.”
Mr Sunak told business chiefs he would not sign a Swiss-style deal with Brussels.
Speaking at the CBI annual conference, the Prime Minister said: “Let me be unequivocal about this, under my leadership the United Kingdom will not pursue any relationship with Europe that relies on alignment with EU laws.
“I voted for Brexit, I believe in Brexit and I know that Brexit can deliver and is already delivering in all those benefits and opportunities for the country.”
However, Mr Sunak’s comments come after Chancellor Jeremy Hunt indicated that the Government would look to eradicate some of the trade barriers created by Boris Johnson’s Brexit deal.