Media playback is unsupported on your device Media caption Nigel Farage: "UKIP own the issue of EU exit"

The campaign to leave the EU is a "united force" and heading for an "historic" victory, Nigel Farage has told his party conference.

The UKIP leader said the in/out referendum pledged before 2018 was "the moment to put country before party".

It could be won with a "big strong, positive message", he predicted.

Meanwhile, UKIP MP Douglas Carswell was involved in a heated exchange with a millionaire donor to the party, the BBC's Robin Brant reported.

Mr Carswell confronted Arron Banks over claims he threatened to have him deselected.

'Hand in hand'

In his speech, Mr Farage told supporters UKIP could "hold its head high" and was "alive and kicking" after the general election when it won just one seat.

UKIP had done "far more" damage to the Labour vote than the Conservatives in May, he added.

Mr Farage hailed a "show of unity" of anti-EU groups, who have formed a group called Leave.eu to push for a UK exit.

UKIP would stand "hand in hand" with this new "umbrella group", he said, suggesting it should become the official Out campaign.

"We are together, we are united, and we believe that the tide has turned," he said.

"I believe that we are on course to win the most historic and the most important political victory in any of our lifetimes."

Image copyright Getty Images

Analysis, by the BBC's Robin Brant in Doncaster

Two things are very clear now: first, there is a broad campaign that's been established by groups on the "leave" side and UKIP is at the heart of that. It's called "leave.eu".

They're the ones who will be sending leaflets to your house, setting up public meetings and trying to friend you on Facebook.

The man who is putting big money up for that, UKIP donor Arron Banks, doesn't want a single face to lead. Nigel Farage sees it differently and it's clear to me after having heard that speech that Nigel Farage is the de facto leader of that campaign.

Second, that is going to be a problem for some on his own side, including some in his own party. He's been criticised for sounding too angry in the past.

Some worry he's too divisive to ensure the "leave" campaign wins. After the speech one senior UKIP figure told me the campaign must be "positive".

To be fair to Nigel Farage he talked of a "big, positive message". The test for him will be can he maintain that in the months ahead.

Mr Farage said a so-called Brexit was "dearer to my heart" even than UKIP, urging activists to put all their energy into the referendum campaign.

"This is the moment to put country before party," he said.

"This is a once in a lifetime opportunity to get back the independence and self-government of this nation."

Media playback is unsupported on your device Media caption Nigel Farage: "We want our country back"

He addressed UKIP's election performance early in his speech, saying: "There are times in life when... you can't change the cards that you've been dealt."

The Conservatives' election victory was the result of "fear from that woman north of the border", he said in a reference to SNP leader Nicola Sturgeon, adding that former Labour leader Ed Miliband was "not really up to being prime minister".

He said UKIP had "owned" the issue of immigration and said he would have bitten the arm off anyone who suggested his party would get the four million votes it achieved.

He added: "UKIP is not only alive and well, not only alive and kicking but is up in the opinion polls from where it was in the general election back in May."