New Ukip leader Paul Nuttall has set himself the aim of raising his party's share of the vote at the next general election as high as 30%.
The eurosceptic party took 13% of votes in 2015 but ended up with just one MP - Douglas Carswell in Clacton.
But Mr Nuttall said that the 27% tally achieved in the European Parliament elections in 2014 - and the 17.5 million voters who backed Brexit on June 23 - convinced him that he can get Ukip's representation in Westminster into double figures in 2020.
And he said that Labour's drift away from its traditional supporters under Jeremy Corbyn and the Conservatives' uncertain approach to Brexit under Theresa May have offered Ukip an electoral "open goal".
"I genuinely believe we can turn it from 12-13% to 26-30%," said the North West England MEP, speaking shortly after his landslide victory in the race to succeed Nigel Farage. "There's so many open goals in British politics, whether it's the Labour Party with Jeremy Corbyn or a Government which I think is about to backslide on Brexit.
"My ambition is not only to get myself into the House of Commons but to get as many Ukip backsides onto the green benches as possible. That's my aim and I believe we can do that."
Ukip will be campaigning for electoral reform to ensure its Commons representation better reflects its share of votes, he said.
But even under the current first-past-the-post system, he said Ukip MPs in double figures was "absolutely realistic".
And he suggested party ranks could be swelled by more defections from the two big parties: "I have had no conversations with anyone from Labour, but I'm sure there are many Labour MPs out there who feel incredibly uncomfortable at the direction that the party is taking under Jeremy Corbyn. But equally, I think there are Conservatives who will be rich pickings as we don't get the Brexit we voted for."
Mr Nuttall said he would be working to ensure Ukip concentrates its efforts on areas where it can win council seats and MPs. He will aim to capitalise on strong Brexit support in traditionally Labour seats in the Midlands and North of England.
"We have to focus our resources," he said. "In the past I think Ukip has had too much of a scattergun approach. That's going to change.
"We finished second in 40 Labour seats at the general election, and that was pre-Jeremy Corbyn. If you look at where those seats are, I don't think people in those areas will sign up to the kind of Labour Party that Jeremy Corbyn leads or are interested in the kind of things Jeremy Corbyn talks about.
"These are the people who are most affected by immigration and crime. They tend to be the most patriotic. They believe in our armed forces. We want to see British people put at the front of the queue - how can it be right that we spending £25 million a day on foreign aid when our NHS is crumbling?
"I also want us to be the party of social mobility that ensures that working class kids have the same opportunities as middle class kids."
As a shaven-headed Liverpudlian with a strong regional accent, Mr Nuttall said he would stand out from the identikit politicians who he believes have turned ordinary working voters off politics.
"One of the reasons we have had progressively lower turnouts in general elections is because since the 1980s we've had this race to the centre and all political parties have started to look and sound the same and we have had politicians with sharp suits and coiffed hair and they don't speak like me," he said. "I think what people are crying out for is a change.
"Ukip is the party of common sense and we will speak the language of working people and address the issues that affect them and not the issues that affect the Islington dinner parties."
He said he stood aside from the summer's leadership contest in the hope of "getting my life back" after a decade in politics. But he changed his mind after seeing Diane James quit as leader and possible successor Steven Woolfe involved in an altercation with a fellow MEP.
Watching reports on TV "literally with my head in my hands", he said he "felt I was watching the party I had helped grow from nothing literally fall to bits".
Mr Nuttall denied he would be overshadowed by his predecessor as leader, who has come to personify Ukip over the past decade.
"I'm my own man. I will be completely different from Nigel," he said.
But he made clear he wants Mr Farage to play a prominent role in Ukip's future.
"If we were offered a seat in the Lords, I would put Nigel on the top of the list, if he wanted to go there," said Mr Nuttall. "Or he could be honorary president if he wanted to be. I want Nigel to be front of the house, not a back-seat driver. I want him on the airwaves on a regular basis."
Unlike Mr Farage, he has distanced himself from US President-elect Donald Trump, and he did not back away from criticisms he made during the presidential campaign about the Republican's comments on women.
"I never backed Trump during the campaign and I said that some of the things he said were appalling and I continue to believe that," said Mr Nuttall. "I'm sure that many people around the country agree that some of the things he said about women were beyond the pale. I thought in many ways he had the right message but he was the wrong candidate.
"I wouldn't cosy up to him, but if the president of the US comes to London, of course I will meet him."