UKIP MEP Paul Nuttall has been elected the party’s leader in a contest to replace Nigel Farage.
The election was the second in the space of a few months, following previous victor Diane James’s decision to step down after just 18 days in the job.
Mr Nuttall took 62.6% of the vote, beating former deputy chairwoman Suzanne Evans, and ex-soldier John Rees-Evans.
The new leader has been MEP for North West England since 2009 and has served as Ukip’s chairman and deputy leader.
Born on Merseyside, he is regarded as well-placed to poach northern working-class voters from Labour.
Of the 32,757 ballot papers sent out, 15,405 were returned with the lion’s share going to Mr Nuttall, while Ms Evans secured 19.3% of the vote, and 18.1% went to Mr Rees-Evans.
Mr Nuttall promised to unite Ukip and “hold the Government’s feet to the fire” over the delivery of Brexit.
“The country needs a strong Ukip more now than ever before, for if Ukip ceases to be an electoral force, there will be no impetus on Theresa May and her Government to give us real Brexit and we will end up with some mealy-mouthed, backsliding version,” he said.
“This will be a betrayal of the British people and a united Ukip under my leadership will never, ever allow that to happen.”
He made clear his sights are on poaching votes from Labour, arguing that the party under Jeremy Corbyn was more interested in “dinner party” topics like climate change and fair trade than the interests of their working class voters, such as immigration and social mobility.
“I want to replace the Labour Party and make Ukip the voice of patriotic Britain,” he said.
“Ukip’s future is bright but for it to be so, Ukip must unite. Today’s result has ensured that it will.”
Mr Farage agreed that the new leader should focus on winning votes from Labour, arguing that there were seats from the Midlands to the North where a majority of Labour supporters voted for Brexit.
“Old Labour voters have absolutely nowhere else to go other than to come to Ukip,” said the outgoing leader.
Mr Farage promised not to be “a back seat driver” but promised he would be available to offer support to the new leader if asked.
He said he would serve out his term in the European Parliament until 2019.
But more imminently, he was this week “going off to the USA - but you will understand, purely as a tourist”.
Mr Farage warned: “If there isn’t a significant electoral threat - and that can only frankly come from Ukip - then the chances are that what we voted for in that referendum will now be significantly watered down. That must not be allowed to happen.”
The outgoing leader said Ukip was in a good position to thrive under its new leader.
“I think everything is to play for and I am happy and confident that I’m handing this over at a good time,” he said.
Mr Nuttall named London Assembly member and former leadership candidate Peter Whittle as his deputy.
Paul Oakden will stay on as party chairman and MEP Patrick O’Flynn - a close ally of leadership rival Suzanne Evans - will be his principal political adviser.
After a summer of discontent which saw rifts, infighting and resignations within the party, Mr Nuttall said: Today is the day that we start to put the Ukip jigsaw back together. It’s day zero, it’s a new beginning.
“That means not only paying lip service to my call for unity, but practising what we preach.
“It means all factions of the party coming together, letting bygones be bygones and sitting round the table together and sorting out our differences.
“This party has a duty to unite. Those at the top of the party owe it to our membership and the four million who voted for us last year but also to the 17.5 million who went out and voted for Brexit.”
To enthusiastic applause from activists at the result announcement in Westminster, Mr Farage said that Ukip’s achievements had helped pave the way for Donald Trump’s victory in the US election and were an “inspiration” to others around Europe who want their countries to leave the EU.
“In this amazing, transformative and in many ways revolutionary year of 2016, it is Brexit that directly led to the establishment being defeated on November 8 and Donald J Trump being about to take up the presidency,” he said.
“We were the inspiration behind that.”
Italy’s constitutional referendum and Austria’s presidential election could deliver more victories for the anti-EU cause in the coming period, while other advances may be made in elections in the Netherlands, Germany and France next year, he said.
“It is Ukip’s achievement getting and helping to win this referendum that says to voters across Europe, if you go out there and turn out, this rotten liberal establishment can be beaten,” he said.
“For those who think 2016 has been an awful year - and I’m not one of them - I’m sorry folks, there is a lot more bad news to come.”
Mr Nuttall’s 9,622 votes gave him a commanding margin of victory over Ms Evans on 2,973 and John Rees-Evans on 2,775.
Defeated candidate Ms Evans offered Mr Nuttall her congratulations and indicated she is ready to work with him.
Ms Evans told the Press Association: “I’m looking forward to working with him. He tells me he has got a role for me so I’m waiting to see what that is.”