So the Ukip mask of respectability, always very thin and ill-fitting, has slipped. After what's now generally known as Nigel Farage's "car-crash LBC interview" and a leader in the Sun saying that the party's position is "racist", the party has been forced to take out a full page advert in the Telegraph to counter Ukip's perception as a bunch of xenophobes.
Just consider the "clarification" Nigel Farage offered, in careful consideration in the cold light of day on Saturday morning: "any normal and fair-minded person would have a perfect right to be concerned if a group of Romanian people suddenly moved in next door". That is a statement that can only be described as bigoted, racist and disgusting. Those "Romanian people" might be doctors, or IT professionals or care workers, or Roma seeking a better life away from prejudice and as likely as any other people to be good neighbours, who'll feed the cat or lend you a cup of sugar.
However, as the Telegraph points out, with probably up to 40% of votes in the European election already cast (by post), the immediate electoral impact may be limited. But it should be a powerful reason for every voter opposed to Ukip's approach to immigration, Europe, charging for NHS services and many other issues to take ten minutes to get to the polling station on Thursday.
What Ukip's rise should do is provoke seriously soul-searching among our political class about why it has been able to get so far with its dangerous, divisive and damaging rhetoric, and been almost unchallenged.
The three largest parties haven't taken on Ukip, but all too often pandered to it, seeking to pull back Ukip voters by outdoing it in rhetoric and policy.
The Tories and Lib Dems have introduced the dreadful Immigration Bill, which seeks to turn landlords and NHS staff into immigration agents. And just this weekend, we saw Ed Miliband again grovelling in apology at the former Labour government's immigration policies. Do we see similar words on its disastrous encouragement of financial sector excesses, of the fact that after 13 years of a Labour government inequality had actually increased? No.
This is not only morally wrong, but politically stupid. By pandering to Ukip's stance on immigration and Europe, the three largest parties have helped to make its claims that immigration has "caused" low wages, has "caused" housing shortages, has "caused" crowded hospitals and schools seem plausible.
It's perhaps not surprising that the Tories, Lib Dems and Labour don't want to dig any deeper, for it's the failed policies of their two successive governments that have given us today's fragile economy and struggling society, both of which are failing to work for the common good.
The fact is that no immigrant from any nation arrives at the White Cliffs of Dover and declares: "I want to work for poverty pay, in awful conditions, without any job security". The state of our job market isn't the result of immigration, but the result of failed economic and pay policies. Labour brought in the minimum wage, an important advance, but then allowed its value to slip down and down, topping up the difference with government benefits that amounted to corporate welfare - subsidising giant profits for multinational companies that aren't paying staff enough to live on, and all too often are forcing them on to zero-hours contracts and into casual hours that send them to food banks.
As for housing, well there are 600,000 empty homes in Britain, many in places with few economic opportunities, while 8 out of ten new jobs created since 2010 have been in London. There are now more bedrooms per person in Britain than ever before - resources, like cash, concentrated in the hands of the few while many are crowded together in often miserable conditions - at the extreme in East London's "beds in sheds".
Inequality and regional disparities, not immigration, combined with the disastrous privatisation of Right to Buy and inflation of a new housing price bubble, plus low wages and ballooning student debt, have created 'Generation Rent', not immigration.
And schools and hospitals? Well we have Michael Gove's disastrous free school policy, spending money with profligate glee on pet projects while not allowing local authorities to plan sensibly for baby booms, the fact that the is NHS bearing the £3bn administrative cost of the Health and Social Care Bill, and the loss of £20bn of so-called "efficiency savings" from 2011 and 2014.
Voters are understandably, rightly, concerned, worried, frightened, about their future and those of their grandchildren.
Additionally, they are increasingly aware that our environment is showing the strain of overuse and exploitation - extreme weather, rising sea levels, polluted air - adding to their concerns.
It's not surprising that Ukip's nasty, simplistic recipe of 'blame the foreigner' has got traction. But it's past time for its claims to be tackled and its prejudice to be exposed. Well done to LBC presenter, James O'Brien, for starting that process.
Now it's up to all of us to continue that. And we need to offer, as the Green Party is doing on Thursday, hope, plans for a better society, one that provides security, comfort and a better life for all.
Follow Natalie Bennett on Twitter: www.twitter.com/@natalieben