Nigel Farage has back-flipped on imposing "arbitrary targets" on immigration, despite Ukip previously advocating a cap on people coming to Britain for employment.
Writing in The Daily Telegraph ahead of Wednesday's major speech on an "ethical" visa system, the Ukip leader wrote that targets would "only result in broken promises".
Appearing on BBC Radio 4's Today programme, Farage strongly hinted at a figure of between 20,000 and 50,000 as his preferred level of immigration, but ruled out setting an exact number, saying people were "bored with targets", in a move that was swiftly seized upon as an awkward u-turn.
Speaking after him on the same show, George Osborne tore into Ukip's "chaotic" immigration policy and Farage's "novel approach to policymaking", saying: "Farage seems to be making it up as he goes along. One minute he talks about a cap, then he ditches it live on air."
Others pointed out that Farage had effectively dumped Ukip's migration target, which the party's migration spokesman Steven Woolfe had unveiled last September, telling activists that the Ukip "commits to bringing UK net migration down to 50,000 people a year for employment".
He restated the aim, saying in October how he "promised to cap migration to 50,000 a year".
At the time of Woolfe's announcement, Sam Bowman, from the Adam Smith Institute, said the party's immigration stance was "intellectually and morally bankrupt", adding: "Despite what Ukip claims, immigration is good for virtually everyone in society, rich and poor alike."
Last month, Woolfe told the BBC's Daily Politics 50,000 was a "gross" target, relating to "those who have the right to work with the option for permanent residence here".
Ukip's Steven Woolfe explaining Ukip's immigration target for people in employment (5:58m in).
The Ukip leader denied suggestions that the party had made a u-turn, insisting that the policy had evolved, telling the BBC: "It isn’t a U-turn. We’ve looked at the figures very closely - 27,000 people would have qualified under the Australian-style points system to come into this country. I can’t see us getting anywhere near 50,000."
Nigel Farage and Steven Woolfe
Asked if people should listen to him or Woolfe, Farage said: "I sat with him yesterday. Policies evolve, they develop, they move on. I don’t want the emphasis from today to be what our cap is."
Farage's big migration push comes after David Cameron was criticised over his failure to deliver on the Conservatives' commitment before the last election to cut net migration to less than 100,000 a year. The Eurosceptic party leader wrote: "While politicians and the people they represent determine the direction of travel for this country, we will not, unlike the other parties, seek to set arbitrary targets which only result in broken promises."
He said that Ukip wanted to ensure that highly skilled people from the Commonwealth were given a "fair chance" to get into Britain, rather than the current situation where precedence was given to European Union nationals.
"From Jewish migration to Windrush, to the Asian migration in the seventies and eighties - some immigrant communities have indeed integrated and made this country a better place," he wrote. "So what Ukip wants is not to do down migrants. It's not to stigmatise, or discourage, or blame people for coming to this country and trying to make a better life for themselves."
Ukip's proposals include an Australian-style points-based visa system which, it says, would ensure the right numbers of highly-skilled workers were able to enter the country while imposing a five-year moratorium on visas for unskilled workers.
Rules discriminating between EU and non-EU nationals would be abolished, and those workers who qualified under the system would be issued with a visa valid for five years. During that time, they would not be entitled to claim UK benefits and would be expected to take out health insurance. After five years they would be entitled to apply for permanent leave to remain, provided they had not broken the law.
Farage said the measures were necessary to bring down a level of immigration that was "unsustainable, unfair, and unethical".
"That's why Ukip has developed a policy focused around an Australian-style points-based system, led by a newly-formed migration control commission, tasked with bringing numbers down, and focusing on highly-skilled migrants and our Commonwealth friends - as opposed to the low-skilled, Eastern European migration that the Tories and Labour have expanded."
On Thursday, Farage delivered a barnstorming speech to an empty room just outside Washington DC, telling several banks of chairs the West must "stand firm" and defend its "Judeo-Christian culture."