Nigel Farage has predicted a “seismic shock” at the next general election if Theresa May has not delivered Brexit by 2020.
Mr Farage said he suspected that the Conservative Government may turn out to be “not fit for the legacy of Brexit”.
And he said he expected a “realignment” of politics which could involve old parties disappearing and being replaced with new ones reflecting the new public mood.
The Ukip leader was speaking at a reception at London’s Ritz hotel to celebrate his contribution to the battle to take Britain out of the EU.
He said he would be sticking around to take part in the battles to come.
Following US President-elect Donald Trump’s suggestion that he should be ambassador to Washington, Mr Farage was presented with a tray of Ferrero Rocher chocolates of the kind handed round at the ambassador’s reception in the famous TV ad.
His speech was heralded by Leave.EU spokesman Andy Wigmore - who joined him at Trump Tower - with a call for attention from “Ladies, Gents, Lords and ... diplomats”.
Mr Farage told the gathering: “We’ve got a problem. In America the revolution is total. Not only have the people spoken and won, but the old administration, Obama and all those ghastly people, are out and the Trump people are in.
“In this country, the people have spoken, but the same players have just been shuffled around the chess board and we are still being run by the career professional political class.
“I am not sure what is going to happen over the course of the next couple of years but I suspect there’s another big seismic shock in British politics perhaps going to come at the next election.
“I suspect that the Conservative party is not fit for the legacy of Brexit. I suspect there is going to be a genuine realignment of British politics over the course of the next three or four years.
“It is unfinished business - the people have spoken but the establishment don’t want to listen. There are great battles to be fought and I’m going to go on fighting those battles.”
The reception at the Ritz was hosted by millionaire Arron Banks, who was thanked by Mr Farage for bankrolling the Leave.EU campaign.
Also present were Conservative MPs Jacob Rees-Mogg and Peter Bone, Labour donor John Mills and Ukip leadership candidate Paul Nuttall.
Asked if he would back the interim Ukip leader for ambassador, Mr Rees-Mogg told the Press Association: “Mr Farage’s relationship with Mr Trump could be beneficial for the country but I am not sure he should be Ambassador Extraordinary and Plenipotentiary.
“Mr Farage is certainly extraordinary in his own way but I think that being plenipotentiary as well may be a bit too much.”
Mr Farage recalled that he had joined Mr Banks and other leading Brexiteers at the Ritz on the morning after the June 23 referendum for a victory breakfast of champagne and kippers - a reference to the nickname for Ukip supporters.
He said: “When people look back in 100 or 200 years, 2016 will be seen as one of the great historic years - a year of big political revolution.
“Brexit was the first brick knocked out of the establishment wall and then look what we got on November 8. The election of The Donald was something of a completely different order.”
To cheers he said: “For those of you who aren’t particularly happy with what happened in 2016, I’ve got some really bad news for you - it’s going to get a bloody sight worse next year.”