Ukip posters that decry "foreign labour" and call on voters to "take back control of our country" have been condemned as racist and bigoted by several political opponents.
But leader Nigel Farage dismissed the criticism of his immigration-centred Ukip poster campaign as wails from the "chattering classes" and said the posters were "a hard-hitting reflection of reality".
Labour MP Mike Gapes said they were "racist" and appealed to "all decent British Commonwealth and EU citizens" to register to vote in May's polls.
The posters were also derided by many on social media, with many calling the stats inaccurate:
Ukip billboards are based on a lie. There is currently a shortage of construction workers in the UK: pic.twitter.com/Uf6rOOfYLh— Adam Bienkov (@AdamBienkov) April 21, 2014
I knew that UKIP poster reminded me of something pic.twitter.com/Y3YfYOUjIA— Sam Freedman (@Samfr) April 21, 2014
Wow. UKIP bunkering down on the anti-immigration stuff. Awful, awful poster. Just awful. pic.twitter.com/3f781AnVJD— Ryan Bourne (@MrRBourne) April 20, 2014
It is a costly campaign for the Eurosceptic party, using £1.5 million of funding from millionaire ex-Tory donor Paul Sykes for its biggest-ever publicity drive ahead of European Parliament elections on May 22.
The posters which warn "British workers are hit hard by unlimited foreign labour" and that 26 million unemployed people across Europe are "after" UK jobs will be displayed on hundreds of billboards across the country.
75% of British laws are made in Brussels, says another poster. Another claims UK taxpayers fund the "celebrity lifestyle" of EU bureaucrats.
Farage said those who compared the posters to those of the BNP were wrong.
"These posters are a hard-hitting reflection of reality as it is experienced by millions of British people struggling to earn a living outside the Westminster bubble," he said.
"Are we going to ruffle a few feathers among the chattering classes? Yes. Are we bothered about that? Not in the slightest.
"Ukip is hugely grateful to Paul Sykes for his magnificent contribution to the great cause of restoring Britain's ability to be a self-governing nation. The political earthquake I have spoken of is on its way."
Sykes said: "I am supporting the biggest advertising campaign in Ukip's history to bring home to the British people what is at stake.
"The European elections are the most important for many years.
"We have the chance to support a party that represents a complete break with the past. The other parties, whatever their merits, are content to work within the existing Brussels straitjacket.
"They cannot do anything about immigration or British workers being undercut by cheap foreign labour and they are prisoners of the European Court of Justice and the closely-related European Court of Human Rights, which stops us deporting foreign criminals and terrorists.
"They are about to embrace new European controls over our policing and justice systems - including the European arrest warrant, they allow interference in our tax system and they subcontract more and more of our foreign and defence policies to unelected EU bureaucrats.
"An overwhelming victory for Ukip will break the political mould in the UK, forcing Labour and the Lib Dems to back a full-scale referendum and intensifying the popular pressure for that to be staged as early as general election day 2015."
The posters will be displayed in two waves over the next four weeks and be accompanied by adverts in digital media.