Ukip deputy chairman Diane James has won the contest to replace Nigel Farage as the party's leader.
The MEP, who was the frontrunner in the contest, took the top job with 8,451 votes.
The new leader said the party had "moved mountains on the political landscape" and was the "change movement of the United Kingdom".
She also said the Government was stealing her party's ideas, calling the prime minister "Magpie May".
Ukip's new leader Diane James has vowed to take on the Tories, but is already facing disagreement within her party having banned Ukip MP Neil Hamilton from speaking at the party conference.
ITV News political correspondent Libby Wiener reports.
Douglas Carswell has insisted he will "absolutely not" quit Ukip after Nigel Farage said he "really isn't doing anything for us".
With the election of Diane James, Ukip has tipped the gender balance in British politics, but true diversity is still some way off.
The grammar-educated former healthcare sector worker made her political name in defeat and holds Vladimir Putin up as a leadership mentor.